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' . _ ' ' - '~‘ - ‘ I. . _ ~ ~ :_. ' ; .. . '1‘: h . “ ' I g ‘ ‘ g 32"", - n: .. z . (T . I ' ‘ . . ’7‘ ' ' I . . , ' . r l . _ n a ' ‘ > - I ‘ ‘ ‘ " I | I' ' r .1 . v) ' V t I .u 'H' i . ‘ - .x I ‘ . I I _ ‘I A .. ‘ . , . . ' ' ‘ - t' 0 i : l l I C I ‘ ' ' a . . 3 . u . - ; ' .‘ ' .' H ' I.‘ I . h. . V I ‘ a ‘ I I I | ‘. ._ L ‘ h. - . II o . i ’ W.- ‘ - - — t ‘ I I ' l I. . _ ... I ' ., ~. I . - ‘ I I . ‘ Q ‘ . ' I K . Y I ' . . ,.. , I .. . O O O I ‘. ' I' ‘ ' . :f' _. . f i I. -~ ‘ ' . Q . “I r v 'I . 0 ' , I_ I O ‘0 I I ' l ‘ I o O . ‘ 0’ I ‘A ' t n "' ' . ‘ . I . ., l. I‘ ,. . . _ , ‘ I I I . n‘ 4‘ | . ‘ . ‘ . ‘ 0 . . I .’ l ‘ . i. '- ' ' I ' . . ‘ ‘ I . - . n . I“ . ‘ ‘ I a I . . —» - - f. _ t ‘L . ‘ ' I ~ '7 “’ ’ . ' V . ~ ' o The.“ 161’ tha Iagma ; I} .. .. . , ; an“: -. ‘. . .' . I ' , ‘ - \. v I. ‘ ,-- - ‘ ‘ A .~ , . I . ' harmed Engineer . ~ < . I I I ‘ . .I . I I ' A T . ‘ . ‘ . I J I . I J ‘ ‘ - VI .._. v.3 " . E . - .. o " ‘ . . ~ I o I I . . | I' ., h I ' . I ‘ ‘ .- \ . ‘. ‘ . 1' - . O I. I O I I V ’ ' ' I Z ‘ IOI : Y " ' I n. z . I I O . . . I o I I ‘ I . . . ' I I ‘. ' I I I ‘ I l . O a .0 T l ' I , I. I ‘ ' U . I . ‘ I I. , o I ’ . O . , | - ‘ . - l ‘JIDI'U‘ 'u')! ‘c . . , ;. . ‘ Ayn; A .: uh.” 1f. . , . , I. all . . . Lfl.". ..y .t . T 1f . #733»??? ~ . ‘I.A.¢ 4 I I . . D l .. . 14¢ . , o u. ‘1' 1 . I ‘I 11.. Q ~:, u.‘ 4‘ o. . . D . A If L ‘. . ,7 ' ail.- .. v. ‘ .thm. 2., . l . .‘ .. r ”I . 4.5!. r , .V. . .3. A; r|u VIVI ‘ . - twp THE NODERNIZATION OF A PLATING ROGM BY ,“ud\ Frank K3 Savage A THESIS Submitted to the Graduate School of Hichigan State College of Agriculture and Applied Science in partial fulfilment of the requirements for the degree of Chemical Engineer Department of Engineering Year 1941 THFS‘.‘ \ ACKNOWLEDCENENT The author wishes to thank the management of C. G. Conn, Limited, for liberal appropriations for the laboratory personnel necessary to carry out the following developments, also for their continued confidence in providing funds for the required production equipment, making a suc- cessful.program possible. Kr. O. E. Beers, General Panufacturing tanager, has at all times offered kindly advice and has taken a tolerant and en- couraging attitude towards inevitable mistakes. Also tr. L. B. Greenleaf, Chief Engineer, and immediate superior, who has always been an enthusiastic coworker and who has contributed many valuable mechanical and chemical sug- gestions in the various developments. Above all, the author wishes to. thank the management for permission to incorporate the information in a thesis for a degree of Chemical Engineer. Most of the developments were carried out with the assistance of Mr. Paul R. Pfefferle, Mr. Ronald M. Fiandt, Nr. Donald B. Reed, and Fr. Charles Shaffer. 3 #1 1342 as... :'-. . - TABLE OF CONTENTS THE MODERNIZATION OF A PLATING ROOM PLATING ROOM PRACTICE 1935 Layouts Figure No. 1, Figure No. 2 SILVER PLATING 1935 Solutions and Equipment Type of WOrk Plated Typical Silver Plating Procedure Operator's Effort COPPER PLATING 1935 Solutions Typical Procedure for Copper Plating Steel Capper Plating Zinc Alloy Die Castings Operator's Effort NICKEL PLATING 1935 Solutions Niekel Plating Procedure Operator's Effort GOLD PLATING 1935 Solutions and Equipment Typical Gold Plating Procedure Operator's Effort ZINC PLATING 1935 Solutions Typical Zinc Plating Procedure Operator's Effort Page 10 10 10 10 ll 11 11 ll 12 1c BRASS PLATING 1935 Solutions Typical Brass Plating Procedure Operator’s Effort METHODS OF SOIUTION CONTROL 1935 REORGANIZATION AND PROCESS DEVELOPFENT Solution Control Analytical Procedures Acid Copper Solutions Cyanide Copper Solutions Greenspan Bright Copper Solutions Brass and Bronze Solutions Zinc Solutions du Pont Bright Zinc Solutions Nickel Solutions Bright Nickel Solutions Silver Solutions Mercury Solutions Gold Solutions Degreasers Alkaline Cleaners and Acid Solutions Factors Analytical Schedules BRIGHT NICKEL Investigation of Processes Equipment Racking Savings Page 12 12 13 13 13 14 14 15 ' 15 17 22 25 46 47 49 50 20 l' v?” II Purification Solution Composition Operating Conditions BARREL NICKEL PLATING Equipment Old Procedure New Procedure Summary of Improvements PLATING ZINC ALLOY DIE CASTINGS Possible Plating Cycle Preplate Treatment Copper Plating Nickel Plating Revised Procedure Comparison of Costs and Quality BRIGHT COPPER Processes Available Amine Bright Copper Development‘Work BATON STAFF PROBLEM Rusting Change in Material AUTOMATIC SILVER PLATING Bright Silver Cleaning Acid Treatment Copper and Nickel Striking Recovery 60 61 62 63 63 63 65 66 t6 67 68 t0 70 7O 72 72 30 I - s. Plating Cycle Pilot Plant'Work Racking Conveyerizing Machine Summary of Silver Developments LAYOUT CHANGES Changes from 1935 to 1940 Changes from 1940 to 1941 PROJECTED FUTURE DEVELOPMENTS ACKNOWLEDGEMENTS ABSTRACT SECTION Page 79 80 81 82 82 83 83 83. 84 84 E5 86 4c THE MODERNIZATION OF A PLATING ROOM PLATING ROOM PRACTICE 1935 Layouts This thesis presents general changes in plating room practice and more specifically changes in one plating room over a five year period from 1935 to 1941. Such developments in electrochemical processing necessarily follow, in general, wmrld wdde prOgress in the industry. The manufacture and finishing of band instruments is sufficiently unique that necessarily many special processes have been developed which are not generally used in the electroplating industry. In order to preperly understand the need for modernization and the sub- sequent improvements it is necessary to describe in detail the equipment and practice as of 1935. Figure No. 1 shows the general plating room layout and location of processing solutions. This plating room.was one hundred fifteen feet long by fifty—four feet wide and had a control laboratory in one corner eighteen feet long by thirteen feet wide. A close inspection of the layout shows that a large number of unnecessary steps was taken by various Operators particularly in plating nickel. This condition was brought about partly by increasing production demands which resulted in locating solutions at disadvantageous places but mostly by a rather radical change in the type of work plated. Reference to Figure No. 2 shows the layout of the same plating room in 1929. This layout although inconvenient in minor details shows a plat- ing rocm.very well laid out for the greater bulk of the work done. At that time demands for cepper, nickel, and zinc plating were greatly increased due to the purchasing of two drum manufacturing plants. The manufacturing plants were moved to Elkhart and existing solutions were moved in and plac- ed whereever there was room. This condition contributed largely to the ~ . G 6 B 3 B B (6:03 gf/ MB N19 N110 NI // NI/Z . » ,«MEO/M was? r 5 Br 2 3 [I 6’3 W i as B 8 : JD W C"? 0/ W” I 8 7 AchZ 851- /V/ /3 £09ng a I..@ -as ._| N14 M! A / 2 a; j 1 ’43 HW 389... A94 A43! 496 A97 A98 M" '-""| @’ - as . w H Ma 6” w 4/ s W Zn/ I ”W B B T'"‘ 49/0 A99 6” A”, h . 6‘8 I I C/V av C L- - _ A /2 @I . u ED 08 (0/ C , I i : W : 500/ £11: pg @ C W A; // W 1402 8 55 n —I as - , I so a 23 356,33}; 8 B 8 8 3 (5002 U f “:1 L fl r fl l_ @ 8 AO/O ROOM 5mm ROOM BRIGHT DIP STORAGE BUFI‘ ROOM 8 F +1 00 t , 6 J O—{g—i t—g—A J O @ PI?’ 6 - SEA/ERA 70R ova, — C VAN/OE COPPER 5/1 7/1 500 - .571 VER DRAG‘ 00 7' 0/? RECOVERY s-JW/rCHBOARo Ace. ~A6/D COP/35R 8/! 7/1 500 -60LD DRAG OUT 0!? RECOVERY B- WORKBINCH CNZ» {YA/woe“ Z/xvc BATH 68R -60LD 351.1. RACKS A -£OC/([R AcZn ~AC/0 Z/NC' BA TH SJ ~J€RA TCH BRUSH JACK I 2 -:¢::Kfi A3 - m um mm 55 JCRUB 55M}! ”‘77 / ~ 46x xv, - NICKEL 5.477% .85 - AURN/J‘H/zvc BARREL 6‘ ~AL KAL M/t' CL [AA/ER 831 /V/— BARREL xv/O/rtz aArH ST - SAND fume; E aAfiRa FAA TING ROOM l:- i (/1; 2;: it M' - a; Ach/V/c/ra 5427/ so - ems/{r pm 0 G CON/V [H - u .. GOLD A779 #3 '- MERCURY DIP ov-cm/wa: 01p 6, - (WHO/WI UM am my - H07 nan-A ELK HA R 7 [”0 50-54wourrop/zn w/ wronocm0me Acm D/P mm-sULPHUR/c ACID om OCTOBER l935 DB "DRY/NG 84/? I?! L son. 5 {‘3 /’ flfldn’fl-fi/fit ' "9 rec-gr pad-31:12?» v-aefl:{!:~;-V 7 5-15 ”taste“ . W B I I. l p B B B G G B 8 B B 3 , <4 ,7, A. . 8 B 5.1.x“? ‘3’? 5;}? C a H Y c ,3 8 HS ’ a ”a D W , bf: CM 11 . E@ _I‘] P E: E M 3 A9, A! 2 NW ~— - s 494 A35 436 497 A58 N15 M6 .3 a i w 8 a W W W" --_ l M [W w M4 HW as 500 ’49 ’0 ”’19 ‘” “MM? c -__ _. I ' : - / A a I :ss Av’ w W C ' ,9 9 so i w ' 600: E] @ cal w ’49 // £51733 5 N c w y c w t-—- -——— --—;. Am? 1 - as w w w R 5 > - — — b—— , B l-I- T ‘8 E g R ""50 a a a a @0 '7 s ACID ROOM U .s'rR/R ROOM ” ZR/efir D/R ” STORAGE BUFF ROOMT @ a % .7 ‘8 J v 67 :a' r v . FDA FCC—4 F—U“. fl/T 6- GfNERA TOR clvca -GYAN/o£ capptR BA m sea - an HR ORls our OR RICO rmr 5-6W/7C/IROARD Accu 'AC/D CORRER 5.47/1 GOO - saw was our OR RICOVIA’Y 6- WORK 8£NCH CW2» -CY/I/V/DE [we 8/! 7/1 65/? -GOL0 851.]. RA cm L - LOG/(ER Ag - 5/4 Viz? BAr/z' 5.7 - SCRATCH BRUSH JAG/1’ o weir/r M - AI/c/ra 5217/! 6‘8 - SCRUB BENCH fay/z. R - WOR/r RACK Au - 60w 547R 09 —- ORV/NO aARRtL c -A£/(A£ w: czamtR c, - ORRO/wwv 547/1 5 a .. aufifl/‘yfi/Ns 5,4335, PLA 7' INS ROOM J- BUFF JAG/r My - //O7 WATER 67' - .94 N0 fuMaz £ RARRtL 6 6. CONN/id w- RINSE fA/VK so - J‘A woucr OR/tR 80 - ems/7'7 DIP - czv-cm/vm/s DIP _ m - HYDROCHLOR/C‘AC/D D/P R9 - MtROURy DIP [UV/ART [”0 A92 9 k DRAW/v Rm: ///0//9¢£ ‘ undesirable layout shown in Figure No. l. SILVER PLATING 1935 Solutions and Equipment In 1935 silver plating was done in twelve different solutions vary- ing in gallonage from fifty gallons to sixteen hundred gallons. The total silver solution volume was six thousand gallons. Eight of these solutions were Operated without agitation while agitation was used in four solutions. In Figure No. 1 silver solutions No. l and No. 2 were two hundred fifty gallons each operated with rotary cathode motion. The cathode rail was circular with anodes on the inside and outside. Solution No. 10 was a nine hundred gallon semi-automatic strike. Solution No. 11 was a semi-automatic plating unit of seventeen hundred fifty gallons. Solution No. 3 was a fifty gallon strike which served solutions No. l and No. 2. Sblution No. 4 was a four hundred gallon strike which served four hundred gallon plating sol- utions Nos. 5, 6, 7, 8 and 9. Solution No. 12 was a four hundred gallon first strike used where two strikes were necessary before silver plating. ~Type of Work Plated The silver plating operations covered a wide range of base metals. These consisted of c0pper, nickel, nickel silver, brass, bronze, and steel in the form of sheet, rod, tubing, castings and assemblies of miscellaneous metals. The size of the parts varied from an assembled Sousaphcne through the entire range of band instruments to piccolo keys. Nearly all work was wired before plating. Very little racking was done at this time. Typical Silver Plating Procedure 1935 There were many modifications in plating procedure to take care of the 'wide variation of work done. The following procedure was typical of the practice. --,," ~_ sq- ft l. Cork and wire. 2. Clean anodically in alkaline cleaner - l min. 3. Fright dip - l to 2 sec. Sulphuric acid - 2 parts. 4. Rinse 5. Hand scrub with pumice. 6. Rinse. 7. Flue dip - l to 2 sec. Hg - .09 to .11 oz./gal. NaCN (free) - 4-5 oz./gal. 8. Rinse. 9. First silver strike - l to 2 min. Ag - .5 oz. T. gal. NaCN (free) - 7 to 10 oz./gal. ' Tank potential - 6 volts. Temperature - room. 10. Rinse (optional). 11. Second silver strike - 10 to 15 min. Ag - .9 to 1.0 oz. T./ga1. NaCN (free) - 6 to 8 oz./gal. stco - 4 to 10 oz./gal. Tank potential - 1.5 to 2 volts. Temperature - room 12. Silver plate - l to.2 hrs. Ag - 3.0 to 5.5 oz. T./g.1. NaCN (free) - 5 to 7 oz./gal. NaZCO 3 - 4 to 10 oz./ga1. Tank potential - .75 to 1 volt. Temperature - room 13. Rinse. 14. Hot rinse. The greatest variation from the above procedure was in the case of keys of which some parts were castings. In order to minimize "spotting out" a phenomanon common to brass castings, a nickel strike was used followed by one silver strike before silver plating. In this case bright dipping, blue dipping, and the first silver strike were omitted from the above pro- cedure. The analysis of the nickel strike solution (No. 5) was as follows: Ni - 2 oz./ga1. I NaCl - 3 oz./gal. H31303 - 3 oz./ga1. pH - 5.8 to 6.2 (colorimetric) Temperature - room Tank potential - 1 volt A statement of the current density used has been omitted from all the above operating conditions. Measurement of current densities on objects as deeply recessed as band instruments is futile due to the fact that at no two spots on an instrument is the current density the same. Even average current density measurements are of no value due to the extreme difficulty of obtaining even approximate area estimations. The weight of deposit nec- essary on each instrument was determined over a period of many years by balancing cOleaints and refinishing costs against the cost of silver applied to each instrument. Specifications on deposits were written in pennyweights per piece and determined by measuring ampere hours of current flow in each instance. This was usrally done with snpere hour meiers, sometimes with £31.15 Ilillnl'fl . . v only ammeters and a clock. Operator's Effort The average operator's time consumed per piece on the average instrument exclusive of the time in processing solutions where the work needed no atten- tion was about twelve minutes. The average number of steps taken per piece were one hundred. COPPER PLATING 1935 Solutions At this time both acid copper solutions and cyanide copper solutions were used for copper plating steel. Three cyanide cOpper solutions were used, No. 1 of two hundred gallons and No. 2 of two hundred gallons for copper striking brass and steel parts before acid copper or nickel plating and No. 3 of two hundred twenty-five gallons for copper plating zinc alloy die castings before running in acid cOpper. Typical Procedure for Copper Plating Steel 1. ‘Wire or rack. 2. Soak clean in alkalinecleaner 4-5 min. 3. Clean cathodically in alkaline cleaner 1 min. 4. Rinse. 5. Acid dip 4-5 sec. l-l Hydrochloric acid 6. Rinse. 7. Cepper strike (cyanide cOpper No. l or No. 2) Cu - .2 - .3 oz./ga1. NaCN (free) - .2 - .3 oz./gal. Na2003 - 2 to 10 oz./gal. Time - 4 to 5 min. Tank potential - 4 to 6 volts. '_. 8. 10. 11. Temperature - 80-9000. Rinse. COpper plate (acid copper #2) Cu - 3 to 4 oz./gal. R280 - 2 to 3 oz./%a1. Time 1 hr. Temperature - room Tank potential - .75 to 1.5 volts. Rinse. Hot rinse. The procedure for slowly building up worn sections in acid copper solution No. l was the same as above. Cu - 3 to 4 oz./gal. H2504 - .5 e../ga1. Time - 12 to 48 hrs. Temperature - room Tank potential - .75 to 1.5 volts. Copper Plating Zinc Alloy Die Castings The solution analysis was as follows: The procedure for plating zinc alloy die castings was as follows: 1. 6. Wipe off hard packed buff dirt. Wire. Soak in alkaline cleaner - 1 min. Cathodically clean in alkaline cleaner Tri sodium phosphate - 3 oz./ga1. Sodium carbonate - 3 oz./gal. Temperature - so to 90° C. Rinse Acid dip - 5 sec. Sulphuric acid - 3% by wt. - 15 sec. 7. 10. 11. 12. 13. 14. 15. 16. 17. 18. COpper plate (Cyanide COPper #3) Cu - 2.5 to 3.0 oz./gal. NaCN - 2-3 oz./gal.l NazCOS - 2.0 to lo oz./ga1. Temperature - 40°C. Tank potential - 1 to 1.5 volt. Agitation - Cathode Oscillation. Stroke - 4 in. A Twenty cycles per minute. Time - 15 min. Rinse. Copper plate (acid Copper #2). Same formula and conditions as Page No. 5 Rinse. Unwire. Copper buff. ‘Wire. Clean as before (Steps 3 and 4). Rinse. Acid dip as before (Step 6). Rinse. Nickel plate, same solution and conditions as given under nickel plating on Page No. 9 Rinse and dry. Nickel buff Operator's Effort The average operator's time consumed per rack or per batch of wired 'work in copper plating steel was about twenty minutes exclusive of the time that the work was in processing solutions requiring no attention. The use of the word batch is in connection with wired work and means the number of wires that could conveniently be handled at once. In the case of racked work from one to two racks were handled at once. NICKEL PLATING 1935 Solutions In 1935 the nickel plating was done in fourteen solutions varying in capacity from seventy-five gallons to four hundred twenty gallons. The total volume of solution used was three thousand seventy-five gallons. These were all cold solutions operated wdthout agitation except in special instances. The work plated was principally brass and copper plated steel. A small amount of steel was nickel plated direct. Copper plated die castings were nickel plated. Aluminum tubing and castings were also nickel plated. The size and configuration varied tremendously. The largest pieces were bugle lyra frames measuring about thirty inches long by twenty inches wide made from hollow tubing, drum shells up to fourteen inches in diameter by six inches deep, and chime tubes up to six feet long. The work graded down to small screws of which fifty or sixty were put on a wire. Nearly all work was wired although racks were used in some cases. Nickel Plating Procedure for Copper, Brass, Copper Plated Steel, and Steel and Copper Plated Die Castings. 1. Wire or rack. 2. Soak in alkaline cleaner - 5 minutes. ‘ 3. Cathodically clean in alkaline cleaner - 1 min. 4. Rinse. 5. Acid dip 4 to 5 sec. 1 to l Hydrochloric acid 6. Copper strike (cyanide copper No. 1 or No. 2). Same formula as on Page No. 5 Time - 2 to 15 sec. 7. Rinse. 8. Nickel plate Solutions (Nos. 5, 4, 8, 9, 10, ll, 12, or 14.) Ni - 3.0 oz./gal. NaCl - 3.0 oz./ga1. H3B03 - 3.0 oz./gal. pH — 5.8 to 6.1 colorimetric Temperature - room Agitation - none Tank potential - l to 1.5 volts. Current density - 1 to 5 amp./sq. ft. Time - l to 2 hrs. 9. Rinse and dry. 10. Buff The c0pper strike was used in the above sequence and others, not for the protective value afforded by such a very thin film of metal, but for two other reasons. The alkalinity of the solution by virtue of its cyan- ide content was found to be a good detergent. It corrected slight imper- fectations in the previous cleaning steps by removing slight grease films, tarnish films, and insoluble soap films induced by immersing'work from the alkaline cleaner in a cold, hard water rinse. The above removal was aided by large quantities of hydrOgen liberated on the work surface which tended to tear and pry the dirt off mechanically in the same way as in an electric cleaner. The other reason for using a copper strike was to cover soft solder used in assembling parts over which nickel has a well known poor adhesion but over which copper has a much better adhesion. 10 Operator's Effort The operator's time consumed in nickel plating work per batch was about twenty minutes exclusive of the time the work was in the tank re- quiring no attention. The average number of steps taken per batch of 'work'was one hundred ten. GOLD PLATING 1935 Solutions and Equipment There were five gold plating solutions in use at this time. Only one of these, a three hundred gallon solution, was used to plate entire horns. This was equiped with a double oscillating work rod which was so construct- ed that each piece could be run individually on one of six separate ampere hour meters. In this way the exact quantity of gold plated on each piece could be controlled to specifications. The other four solutions were ten gallon crooks, one of which was used for sponging and the others for heating gold solutions to gold plate the inside of horn bells. This was done by corking the throat of the bell, supporting the horn upright with the bell end up, and placing a circular rubber around the rim of the bell to keep solution from dripping out when the bell was filled above the rim. After filling with warm gold solution a cathode contact was made on the horn'with a bulldog clip and a platinum anode was inserted. The current flow was regulated on small bells by the depth the anodes were inserted. 0n large bells a sheostat and ampere hour meter were used together with a ro- tating anode to give solution agitation. The basis metal in most cases was the same as in silver. (Page No. 2) Typical Gold Plating Procedure 1935 1. Before gold plating the horns were first silver plated as on Page No. 3 2. Scratch brush. 3. Scak cleaner - 2 to 3 min. 11 4. Scrub - (Pumice). 5. Gold plate. Au - 4-5 dwt./ga1. NaCN (free) - .1 to .5 oz./ga1. Na C03 - 6 to 8.oz./gal. 2 Ha P04 ". e25 OZe/gale 3 Temperature - 40° c - 50° 0 Tank potential - l to 1 1/2 volt. Time - Depending upon specifications. Operator's Effort The average time consumed in gold plating a typical horn such as a cornet or trumpet exclusive of the time the horn was in the solution requiring no attention.was fifteen minutes. The average time consumed for a bell only was five minutes. The average number of steps taken in either operation was about thirty. ZINC PLATING 1935 Solution Only one zinc plating solution was used to plate zinc finishes. The other solution, the cyanide zinc bath, was used to strike aluminum before attempting to nickel plate. The solution for zinc finishes was an acid zinc solution Operated without agitation. The work plated in this solution was principally steel flesh hoops around which drum heads were tucked. These finished hoops did not show and all that was desired was to rust proof the steel. Typical Zinc Plating Procedure 1935 1. Soak clean - 4 to 5 min. 2. Cathodically clean - 1 min. 3. Rinse. 4. Acid dip - 15 sec. 12 1-1 HCl 5. Rinse. 6. Copper flash - 1 min. 7. Rinse. 8. Nickel flash - 5 min. 9. Rinse. 10. Zinc plate - 15 min. Zn - 6-7 oz./ga1. pH - 4.5 The author never learned just why the above plating procedure was used. It appears to be an excellent example of tradition in plating room practice. The zinc solution contained quantities of other materials than those men- tioned, particularly aluminum salts, added probably for buffering action. Operator's Effort The average time required in zinc plating one batch of work exclusive of the time the work required no attention was twenty minutes. The average number of steps taken was about one hundred thirty. BRASS PLATING 1935 Solutions There were two brass solutions Operated at this time, one small one of thirty gallons which was used to put a special brass finish on aluminum bugle lyra bars and a four hundred gallon solution which was used for apply- ing ornamental brass finish on steel drum parts. This brass finish called "nobby gold” was subsequently lacquered with clear lacquer. In 1935 the "nobby gold" finish was nearly a thing of the past, and very little brass plating was done. The special finish on the aluminum bars was discontinued shortly thereafter. The two’brass solutions were of very nearly the same analysis the small one being slightly lower in free cyanide. 13 Typical Brass Plating Procedure 1935 1. Soak clean - 5 min. 2. Cathodically clean - 1 min. 3. Rinse 4. Acid dip - 15 sec. l-l HCl 5. Copper strike (solution #2) - 5 to 10 sec. 6. Rinse 7. Brass plate Cu - 4.0 oz./ga1. Zn - 1.5 oz./ga1. NaCN - 3.5 oz./gal. EaZCO3 - 4 to 10 oz./gal. Temperature - 55°C to 45°C Time - l to l l/? hrs. Agitation - none Tank potential - 1 to 1 1/2 volts Operator's Effort The average number of steps taken in brass plating one batch of work was one hundred ten. The operator's time consumed was about twenty min- utes. HETEODS OF SOLUTION CONTROL 1935 During a few depression years prior to 1935 no chemist was employed by the company. No standard methods of analysis or solution control were used. What little was done was performed by one of the operators who had no technical training and little chemical knowledge. No definite schedules were followed as to frequency of analysis. In many cases an analysis was run only if a solution was giving trouble. In spite of these inadaquacies as late as 1935 a good job of plating was being done even though a steady 14 flow of production due to solution troubles, was not had at all times. The author'wishes to pay tribute, with all humility, at this time to the old practical forman plater, today nearly a thing of the past, who armed only with a thermometer and hydrometer, a sense of smell and taste, no knowledge of chemistry, denied at times the use of the essential ammeter, still applied electrodeposits sufficiently well to build a ground work for the present day large industry. REORCANIZATION AND PROCESS DEVELOPMENT Solution Control The author has collected, tested and used many procedures for the analysis of plating solutions. The procedures have come from so many sources that due credit cannot here be given for each specific scheme. Only a few modifications are due to personal ingenuity. The following procedures are given because it is believed that this will be the first time as complete a scheme for as many solutions has been collected and and correlated. These procedures are in places, of questionable accuracy but have all been used in actual solution control and have been found sufficiently accurate for routine control work. I. Copper 15 PROCEDURE FOR ACID COPPER SOLUTIONS A. Solutions 1. Na. 8 0 01 Ne 25 1‘. Le 223 s / a. weigh accurately app. .2 gr. Cu. b. Dissolve in 5cc HNOS, boil to expell N02. c. Cool, add 25cc H 0, add NH 2 4 d. Add 10cc HAO (Acetic acid) to strongly acid, light blue OH to deep blue. e. Boil 1-2 minutes, cool, dilute to 150 cc. f. Add 3 gr. K1, 2 cc starch solution. g. Titrate with Na28203_to end of blue color. h. gm Cu chaZSZCS : f 3 gm Cu/bc NaZSZO3 B. Procedure 1. 2. 5. 4. 5cc of plating solution, add 5 cc H 804, few drOps END 2 3' heat to $03 fumes. Follow above procedure from step (c) on. After addition of HAc add 6 so 50% KF solution. (cc Na 0 ) (factor) (26.8) 3 Oz. Cu/gal. 282 . II. Determination of copper in plating solutions by Electrolysis A. Procedure 1. 10 cc sample of acid copper solution, add 3 cc H 804, add few 2 drops HN05, evaporate to copious fumes of 803. Treat as below from step three on. 10 cc sample of strong cepper cyanide solutions, 25 cc sample of weak solutions. Add 8 cc H2804, cautionI under hood, few drops HNOS, evaporate to copius fumes of $03. If solution does not clear up upon evaporation, add few drops more HNO3 and con- tinue evaporation. 16 3. After evaporation, add few drOps more HN03 dilute to 150 cc. Cover with split watch glass. Electrolyze over night at 1/2 to 3 /4 amp. or 3 amps. for 3 1/2 hours. Wash down sides of beaker and cover glasses with water. Continue electrolysis until there is no test for copper with fresh H28 water. 10 cc sample, (wt. deposit) (13.4) - oz. Cu./gal. 5 cc sample, (wt. deposit) (26.8) : oz. Cu./gal. III. Sulphuric Acid A. B. Solutions 1. Methyl orange indicator. 2. Sodium Hydroxide .1 N. 4 gin/L. a. Standarize as given on Page No. 47 b. 1 cc .1 N. NaOH : .0049 gm H2804. c. gm H2804 : 1 cc NaCH soln. is factor. Procedure I 1. 10 cc plating solution dilute to 100 cc. 2. Add M. 0., titrate with NaOH to slight yellow. 3. (chaOH) (factor) (13.4) 2 oz. HZSO4/gal. 17 PROCEDURE FOR CYANIDE COPPER SOLUTIONS 1. Copper A. C. Solutions 1. Nazszos same as acid cepper. (Page No. 15) Procedure 1. 10cc of cyanide copper solution, dilute to 100cc. 2. Add few cc sat. Na S solution. 2 3. Make slightly acid with .5 N. HCl (avoid excess) 4. Filter, wash thoroughly with hot water. 5. Place paper and ppt. in beaker, add 5 cc H303. 6. Heat to expel N02, cool. 7. Add NH40H to deep blue, make acid with acetic acid, boil 1-2 min. 8. Cool, dilute, add 2-3 gr. KI (excess), titrate with KaZSZO3 9. (cc NaZSZOE) (factor) (13.4) - oz. Cu/gal. Optional Method 1. 10cc sample of plating solution. 2. Add 10cc H 804 and 1/2 cc HNO5 under well ventilated hood. 2 3. Boil to expel HON fumes until dense white fumes of 803 are copiously evolved. 4.. Dilute with 25cc water, add Soc of bromine water to oxidize arsenic and antimony, boil off excess. 5. Follow above procedure from step (7) on - add 5 cc 50% RF after addition of acetic acid to reduce iron concentration. II. Free Cyanide A. B. Solutions 1. AgNO .01 N. weigh exactly 1.6989 gr. AgNOs. Make up to 1L. 3 Procedure 1. 10cc cyanide plating solution dilute to 1500c. 2. Add few drops 2% KI solution, titrate with AgNo3 to faint cloud. 18 3. (cc AgNOs) (.0134) : oz. NaCN/gal. Note - For cepper solutions containing over .5 oz. NaCN/gal. use 1/10 AgNOS. III. Carbonate A. Solutions 1. HCl about .2 N. 16cc concentrated acid/1» Standardize against standard NaOH or very pure NaZCO3 with methyl orange indicator. Gr. NazCOS : gr. NaZCOS/bc HCl solution (factor) cc HCI 1cc N/io 501 : .0053 gr. Nazco3 3 (factor) B. Procedure 1. 1000 plating solution. Add 1 cc NE4CH dilute to 5000. 2. Heat nearly to boiling, add excess BaCl2 solution. 3. Filter, wash with hot water several times. 4. Put ppt. and paper in beaker, dissolve in standard HCl, titrate excess with NaOH using h. 0. (See note). 5. (cc HCl-HCl equivalent of NaOH) (factor) (13.4) = oz. NagCOS/gal. Note - In step 4 when dissolving ppt. add 10-15cc standard HCl in excess after M. 0. turns red. Let stand for 10-15 min. before back titrating with NaOH. IV. Rochelle Salts I A. Solutions 1. Oxalic Acid .1 N. a. Weigh out exactly 6.305 gm H2C204.2H20. Dilute to 1L. 2. Potassium permanganate. a. 'Weigh out approximately 3.16 gm. Khn04. Hake up to 1L. b. Standardize against oxalic acid solution by the same method as given in the procedure. 19 (weight of oxalic acid peed) (1000) : Normality of Ki'no4 T CC KIKIIO4 (63) B. Procedure 1. 3. 9. 10. 11. 12. 13. 500 of plating solution, transfer to a 25000 beaker, add 200 of concentrated hydrochloric acid. Boil 20 min., do not allow the velume to fall below 200. This operation should be carried out in a hood to avoid inhaling the hydrocyanide acid which is evolved. The solution should be clear and have the greenish color char- acteristic of copper chloride. Dilute to 5000 with distilled water, and add about 2 grams of zinc dust or granulated zinc. Shake periodically for about 30 min. to precipitate all the copper. Filter and wash the precipitate thoroughly with distilled water. At this stage, the solution should be colorless and clear. Add 500 of concentrated sulphuric acid and several crystals of manganous sulphate (less than 1 gram) to the combined filtrate and washings. Heat almost to boiling. When the solution has reached the proper temperature and the crystals have dissolved titrate with tenth normal potassium permanganate solution, with stirring, until an excess of a few 00 has been added. The solution at this point shows a brownish turbidity due to the presence of precipitated manganese dioxide. Clear the solution with 5 or 1000 of tenth normal oxalic acid. Heat almost to boiling once more. Add more permanganate solution until the pink color which appears on the addition of each drop persists for at least 1 min. 14. 15. 16. 20 One 00 of tenth normal potassium permanganate is equivalent to 0.0047 gram (0.11163 oz.) of Rochelle salt (NaKC4H406.4H20). Calculate the Rochelle salt from the total amount of tenth nor- mal potassium permanganate solution and the amount of tenth normal oxalic acid used. For a 500 sample, this difference, 'when multiplied by_0.94, gives the result in grams/liter, or by 0.125 oz./gal. (cc .1 N. KMnO4 - KRnO4 equiv. of oxalic acid) (.125) 2 oz. Rochelle salts/gal. This method for determining tartrate in cyanide copper plating solution gives reproducible results, and is accurate enough for control purposes. V. Rochelle Salts (Optional method) A. B. Solutions 1. Sodium hydroxide .1 N. See acid copper Page No. 16 2. Thymolphthalein indicator. Procedure 1. 1000 sample of plating solution in 25000 beaker. 2. Add 1000 concentrated hydrochloric acid, 1500 distilled water, and boil until liquid is greenish in color and free from turbidity. 3. Add 1000 of a 15% solution of sodium sulphide, while stirring, let settle, and filter. Wash'with small amounts of distilled wmter to which has been added a few drops of sodium sulphide and sufficient hydrochloric acid to render wash water faintly acid to litmus paper. 4. Boil the filtrate collected in a 25000 bealer until its vol- ume is reduced approximately l/I3 and add 35% potassium carbanate. Note — If precipitate is evident at this stage filter before adding potassium carbonate. 7. 8. 10. 21 Evaporate until volume is reduced by 1/2 and add glacial acetic acid until solution is just acid to litmus. Continue to evaporate until the volume has reached 20 or 2500, remove from hot plate, stir in 700 of glacial acetic acid and let stand 15 min. with occasional stirring. Add 10000 of 95% ethyl alcohol and let stand 15 min. with occas- ional stirring. Filter and wash four times with 2500 portions of ethyl alcohol or until the washings are neutral to litmus paper. Transfer filter paper to beaker in which ppt. was made, add 15000 distilled water, 5 drops thymolphthalein indicator and heat to boiling. Titrate with .1 M. sodium hydroxide until one drop produces a faint blue color. The number of 00's multiplied by .378 equals oz./ga1. Rochelle salts in plating solutions. Note - Where over 6 oz./gal. of Rochelle salts or over 1/2 oz./ gal. of iron is present, a 500 sample should be taken instead of 1000 portion. I. Copper 22 GREENSPAN PRICFT COPPER A. Solutions 1. 2. K1 soln. 30% NaZSZ 3 .1 N. Make up and standardize as on Page No. 15 B. Procedure 11. 1000 sample of soln. in 30000 Kjeldahl flask. Add .5 gm HgSO4 Boil to light green color or colorless Add 1000 H2804 (conc.) Heat cautiously until foaming ceases, and then hotter to fumes of SO3 A Cool, dilute to 12500 Add NH40H (cone.) to deep blue color. Add 1000 EA0 (glacial) to strongly acid Add 1000 XI soln. (30%) Add few drops starch solution and titrate with .1 N. Nazszo3 to end of blue color (00 .1 N. Na28203) (.68) : oz. CuSO4 . SHZO/gal. II. Total Sulphate A. Solutions 1. Rec 12 1 ['5 B. Procedure 1. 500 sample, silute to 30000 Neutralize with 501, add 500 501 excess (conc.) Heat to boiling, add-dropwise while stirring 1000 BaCl soln. 10% 2 Keep hot several hours ar allow to stand overnight Filter through gooch crucible ‘Wash, dry, ignite, and weigh 23 7. (wt. Beso4 ppt.) (37.7) = total sulphate as oz. (NH4)ZSO4/gal. III. Ammonium Sulphate (Combined ammonia) A. Procedure A 1. (Value for copper sulphate) (.53) = AmnOnium sulphate equivalent 2. (Total sulphate II B 7) - (Amm. Sulp. Equiv. III A 1) : Ammonium sulphate (NH4)2 804 IV. Total Ammonia (As ammonium sulphate A. Procedure 1. 1000 sample, dilute to 15000 in 30000 flask 2. Add 2 gm NeOH pellets and several pieces of broken porcelain 3. Connect to a condenser through a Hempel fractionating column 10" to 12" long as quickly as possible. 4. Distill slowly until volume is reduced to about 1/3 5. Collect distillate in a 60000 beaker containing 5000 .1 N. HCl 6. Vapor in distillation should not be over 100°C to avoid loss of amino 7. Flush condenser into beaker with distilled water 8. Add 100 bromcresol purple indicator .04% or 3 or 4 drops of methyl red. ‘ 9. Titrate with .1 N. NaCH to color change ‘ 10. (00 .1 N. - cc .1 N. H01) (.176) : total ammonium oz./gal. as ammonium sulphate V. Free Ammonia 1. (Total ammonia - Combined ammonia) (.86) : oz. 26% aqua ammonie/gal. VI. Total Nitrogen A. Procedure 1. 500 sample, place in Kjeldahl flask 2. Dilute to 2500, add 5-1 H2804 to disappearance of blue color, than 10. VII. Amine 1. 24 add 1000 conc. H2804 Add .2 gm HgSO4 and 5 gm anhydrous Na2S04 Heat to fumes of $03 and continue with strong flame for 1 hr. Put several small pieces broken porcelain or one piece gran- ' ulated zinc in the flask and enough 50% NaOH to make mixture alkaline Connect quickly to condenser and adapter dipping into 60000 beaker containing 25000 water and 5000 .1 N. HCl Distill until volume is reduced to 10000 Flush out condenser into beaker with distilled water Add 100 .04% bromcresol purple indicator or 3 or 4 drops of methyl red indicator, titrate with .1 N. NaOH solution until indicator changes color (00 .1 N. HCl - 00 .l N. NaOH) (.88) - total nitrogen as oz./ga1. ammonium sulphate (oz./ga1. total nitrogen — oz./gal. total ammonia) (.0665) - oz. diethylenetriamine/gal. 25 PROCEDURE FOR PPASS AND BRONZE SOIUTICNS I. C0pper A. Solutions 1. Same as cyanide copper. Page No. 17 B. Procedure 1. _II. Zinc 10cc sample, add 10cc H so4 and 1/2 00 5103, boil to so3 fumes. 2 (Under hood) Boil, 0001, add NH40H to deep blue Add HA0 to strongly acid, boil 1-2 minutes Cool, dilute to 15000, add 3 gr. KI Titrate with Na28203 and starch (chaZSZOS) (factor) (13.4) : oz. Cu/gal. A. Solutions 1. Same as for zinc solutions Page No. 27 B. Procedure 1. 2. 1000 sample, dilute to 5000, heat to 60°C Heat gently, add excess sat. Na S solution, stir, heat few 2 minutes, filter, wash with warm water. The zinc ppt. should be white at this point, if not, add NaCN to whiten it. Return the ppt. and paper to beaker, add 2000 1-1 HCI, b0i1 10 min., 0001 Just neutralize with KP4OF, make just acid with 1-1 HCl, add 300 concentrated HCl excess Dilute to 15000, heat nearly to boiling, add 100 FeSO4 solution Titrate hot with K4Fe(ClI)6 from blue to green (Factor) (cc K4Fe(CN)5) (13.4) : 02- Zn/éalo III. Free cyanide 26 A. Solutions a. b. 0. d. 24.16 gr. Cu(N03)2 in 1 L. water weigh accurately app. .5 gr. KCN (pure) Dissolve in 10000 water Add 1000 NH4OH, titrate with Cu(N03)2 solution until blue color persists l min. _(gr. KCN) (.753)g: Gr. NaCN/00 solution (factor) (00 Cu(N03)2) ~B. Procedure 1. 1000 sample of plating solution 2. Dilute to 5000, add 1000 NH 0H 4 3. Titrate with Cu(N03)2 until blue color persists 1 min. 4. (cc Cu(N03)2) (factor) (13.4) : oz. NaCN/gal. IV. Carbonate A. Same as Cyanide Copper, Page No. 17 V. Notes 1. It is impossible to get a good and point if there is not suf- fivient zinc present to use several 00 of K4Fe(CN)5 solution. In this case add a known amount of zinc as ZnClg to the sol- ution before titrating and subtract that amount from the answer. 27 PROCEDURE FOR ZINC SOLUTIONS I. Zinc A. Solutions 1. K4Fe(CN)6 a. 44 gr. K Fe(CN) ) 4 6 ) l L. water b. .3 gr. K3Fe(CN)6) 0. Age six weeks d. Standardize against .2 gr. Zn dissolved in 2000 1-1 HCl as given in procedure from step B 3 on, or standard zinc solution 0. (gm Zn) : ngn /'100 K4Fe(CN)6soln. (factor) (00K4Fe(CN)6) 2. FeSO4 a. 3 gr. FeSO4 b. 1000 HCl 0. l L water B. Procedure 1. 1000 sample of cyanide zinc solution, 500 sample of acid zinc solution 2. To the cyanide solution add 1000 HCl (under hood), boil 10 min., 0001 3. To either solution dilute to 10000 add FH40H to just alkaline then 1-1 HCl to just acid 4. Add 300 concentrated HCl excess 5. Dilute to 20000, heat almost boiling, add 100 F6804 solution 6. Titrate-with K4Fe(CN)6 solution to color change from blue to green 7. (00K4Fe(CN)6) (factor) (13.4) 3 oz. Zn/gal. (cyanide) (00K4Fe(CN)6) (factor) (26.8) : oz.zfi/ga1, (acid) 8. See note on zinc in brass solutions. Page No. 26 28 II. Total Cyanide A. Solutions 1. 10% KI solution 2. .1 N. AgNO3 solution 3. 10% NaOH solution B. Procedure I l. 500 sample of plating solution 2. Add about 500 of 10% NaOH and few drops of 10% KI solution 3. Titrate with .1 N. AgNO3 t0 faint, permanent, yellow turbidity. Stir vigorously during titration ‘ 4. Add a little more NaOH, if the turbidity disappears, continue titration until a permanent turbidity is produced 5. (cc AgNO3) (.262) f 02. NaCN/gal. C. Notes 1. The total cyanide is determined because in the presence of NaOH, not even a good approximation of free cyanide can be obtained. 2. Titration is not affected by aluminum salts or tartrateé, but the result is high in the presence of ammonium hydroxide. 3. Sodium zincate (NaZZnOz) and the double zinc sodium cyanide (NaZZn(CN)4) are both present in the zinc plating solution so that it is difficult to calculate the uncombined sodium cyanide with any degree of accuracy III. Total Alkali A. Solutions 1. Potassium ferrocyanide as used for zinc titration. 2. Silver nitrate as used for total cyanide titration 3. .1 N. hydrochloric acid B. Procedure 1. 5 cc of plating solution IV. 2. 29 Dilute to 15000, add slightly more than enough K4FeCN6 to ppt. the zinc (slightly more than 1/2 that required in I). Add slightly more AgNO than amount required in II. 3 Add few drops of phenolphthalein, titrate-with N/lo 501 until pink disappears for a few minutes. By this method, the total alkaline hydroxide plus one half the carbonate is determined. 6. 100 .1 N. HCl 2 .004 gr. NaOH (.004) (26.8) (cc .1 N. HCl) : oz. NaOH/gal. (Uncorrected) 7. (oz. NaZCOS/gal.) (.377) : oz. NaOH/gal. (Correction) 8. (oz. NaOH/gal. step 6) - (oz. NaOH/gal. step 7) : oz. NaOH/gal. (Corrected) C. Notes 1. Correction is not necessary unless NaZCOS or ZnCO3 has been added or unless the solution is old 2. In the above titration, the carbonates have been changed to bicarbonates. 3. The calculation (step 7) allows for only one half the carbonate content as found in IV Carbonate A. Same as for cyanide copper solutions. Page No. 18. Acidity A. The acidity of acid zinc solutions may be titrated in the absence of weak acids, but it is better to measure the pH either by electrometric or colorimetric methods. 1. II. III. 30 ANALYSIS OF DU FONT ZINC Zinc (Same as for cyanide zinc solutions Page No. 27) Total Cyanide Determination (Same as for cyanide zinc solutions Page No. 28) Caustic Soda Determination A. Solutions 1. 2. .1 N. 112504 50 gm/i. a. Standardize against standard NaOH solution Sulpho-orange indicator B. Procedure 1. 2. 3. 3. Pipette a 1000 sample into a 250ml Eflenmeyer flask Add 1000 water and 1 gram sodium cyanide and 5 drops sulpho- orange indicator Titrate with 1 N. Sulphuric acid to a color change from red- orange to yellow green or lemon color as end point. CAUTION This method involves the titration of acid into a cyanide solution. Avoid adding excess acid. At the proper end- point the solution will still be alkaline. Use granular sodium cyanide rather than a solution of NaCN be- cause NaCN slowly decomposes into ammonia and in an aqueous solution which would make results high. The titration should be made in good light so the color changes can be accurately noted. Sodium cyanide must be added so that all of the zinc which is present is in the form of Ne22n(0N)4 (Sodium zinc cyanide) and not as NaZZnOZ (sodium zincate) since the zincate is not titrated. Results will belOw if insufficient NaCN is added. IV. 31 5. Calculations (cc NHZSO4) (.536) : oz. NaOH/gal. Carbonate Determination (Same as for cyanide 00pper solutions Page No. 18) I. II. 32 PROCEDURE FOR NICKEL SOLUTIONS Nickel A. Solutions 1. AgNO3 .1 N. a. Same as free cyanide for Cu Page No. 17 2. KCN .2 N app. a. ‘Weigh accurately about 10 gr. KCN, make up to 1L. b. Dissolve about .1 gr. pure nickel weighed accurately in 500 HNO5 0. Heat to expell N02, dilute to 2500 (H20), add 1000 NP40H dilute to 15000 d. Add few drops KI solution (10%) a. Add .1 N AgNO3 until permanent cloud f. Titrate with KCN until cloud disappears g. Bring back'with AgNOB, finish titration with KCN to clear solution h. Compare solutions (lcc AgNO3 : X00 KCN) using KI indicator (wt. Sample) (co KCN) - (Agh'o3 equiv. of KCN) : wt. Ni/bc KCN (factor) i. 100 .l N KCN : .001467 gr. Ni 8. Procedure 1. 500 sample of plating solution, dilute to 5000 (H20) 2. Add few drops of tartaric acid, add 500 NH40H, dilute to 20000 (H20) 3. Add few drops KI and titrate as above 4. (cc KCN - KCN equiv. of AgNOs) (factor) (26.8) = oz. Ni/gal. Factor : .001467 XN Optional Nethod for Nickel A. Solutions III. IV. E. 33 l. Ammonium hydroxide C. P. 2. Dimethylglyoxime 1% alcoholic solution. Procedure A 1. Take 1000 sample of nickel solution (2500 if nickel content is less than 2 oz./ga1.), add 500 H2504, evaporate to SO3 fumes, 0001, neutralize with NH4OH 2. Add 2 gr. of (NH4)2804 and 2000 of NH4OH, dilute to 100cc 3. Electrolyze at .2-.25 amp., if not agitated, for at least 4 hrs. using platinum electrodes 4. When the blue color of the solution has disappeared and a drop of the solution produces no pink color with dimethylglyoxime, the electrolysis is Complete. 5. wash, dry, and weigh the cathode. The increase in weight is the nickel in the original sample. 6. (wt. Ni) (13.4) : Ni oz./ga1. Chloride A. Solutions 1. AgR03 .1 N 16.989 gr./1 2. K20r04 10% solution B. Procedure 1. Take 500 sample of nickel solution, dilute to 10000 2. Add lco KZCr04 solution, titrate-with AgNO3 (.l N) to light buff color 3. (cc AgNOs) (.156) : oz. Na/Ul/gal. (00 A5303) (.1434 3 oz. NH401/gal. (cc AgNOS) (.1735) : oz. NiClz/gal. (cc AgNOS) (.316) 3 oz. NiC12 . GHZO/gal. Sulphate A. Solutions 1. 34 I BaC 12 107. B. Procedure 1. 2. 3. 6. 7. 500 sample of nickel solution dilute to 20000 Add 1000 C. P. HCl, 1000 alcohol, boil Add excess 10% BaClz solution (20cc for 30 oz. ha2504/gal.) slowly, stir, keep hot for 2 hrs. Filter, wash free from chlorides, ignite in gooch (wt. BaSO4) (16.26) _ oz. NaZSO4/gal.) ) Total sulphate oz. NgSO4/ga1. ) (wt. Ni oz./gal.) (2.42) : oz. NaZSOg/gal. (Combined) (wt. BaSO4) (13.82) (wt. total Na2804)-(wt. combined Na2804) : oz./gal. Na so4 2 V. Magnesium Sulphate A. Solutions 1. 2. Dimethylglyoxime 1% alcoholic solution Sodium amonium phosphate 10% solution B. Procedure 1000 of nickel solution Add 5000 NH40H Electrolyze at 1.5 amperes until there is no trace of Ni with dimethylglyoxime Add 1500 10% sodium ammonium phosphate Stir for 30 minutes; or let stand for 3 hrs. Filter through gooch and blast Weigh as Ng2P207 and calculate to Ng804 (wt. ppt.) (2.1212) (13.4) 3 oz. NgSO4/gal. VI. Boric Acid A. Solutions 1. 2. NaOH .1 N 4 gm./i. Standardize as on Page No. 47 Bromcresol purple .04 gm./5000 alcohol 35 B. Procedure 1. 500 sample plating solution Add mannite to make thin paste Add 10 drops bromcresol purple indicator Titrate with NaOH solution to purple end point (cc .1 N NaOH) (.166) z'oz. HsPog/gal. VII. Boric Acid (Optional Method) VIII. A. Solutions 1. NaOH .1 N 4 gm./L. Standardize as on Page No. 47 2. Indicator-Heat 10000 glycerine to 1000-120O F, add .02 gm. methyl red, dissolve. Solution when made up should be a bright lusterous red. Procedure 1. 2500 sample plating solution 2. Add 2500 neutral glycerine 3. Titrate with standard NaOB until a drop from end of stirring rod, produces an orange color when mixed with a drop of the indicator on the spot plate. 4. If the titration is carried too far the color is yellow in- stead of orange. 5. 30.1cc .1 N NaOH : l oz./ga1. 143503 (25cc sample) 6. (cc .1 N NaOH used) : oz. HSBOB/gal. (30.1) Zinc as an Impurity A. Solutions 1. 501 (1-4) 2. 52504 (1-1) 3. H2504 (1-4) 40 118011 (2%) B. 36 5. K4Fe(CN)6 soln. as in zinc analysis Page No. 27 Procedure 1. Take 10000 sample of nickel solution in 60000 beaker add 300 - 00 cold water. 2. Pass a rapid stream of H23 gas through the solution for 40 min., filter, wash well with cold water. 3. 'Without puchering the paper dissolve the ZnS of the ppt. with cold HCl (1-4) into original beaker, add 15cc H2804 (1-1), evaporate to dryness. 4. Dissolve salts in beaker with 10030 water neutralize with NaOH (203;), acidify with H2804 (1-4) and add See 112504 (5%) in excess. 5. Dilute to 20000 with cold water and reppt. with H28 for 40 min. 6. Wash and dissolve ppt. as before, neutralize with NH40H make just acid with HCl and add 200 HCl (concentrated) in excess. 7. Titrate solution with K4Fe(CN)6 exactly as done in analysis of zinc solution from step (I-B-5) on Page No. 27 8. (cc K4Fe(CN)6) (factor) (1.34) : oz./ga1. I. II. III. 37 METHODS OF ANALYSIS FOR BRIGHT NICKEL SOLUTION Nickel Same as Cobalt white nickel, Page No. 32 A. Solutions 1. 2. 3. Sulphuric acid (1-5) Sodium Hydroxide (conc.) Starch solution Sodium thiosulphate .1 N. Standardize against pure 00pper given under 00pper solutions. lcc N/lO Na 8203 I .00636 gm. 2 Cu Page No. B. Procedure 1. 2. 3. 4. 6. 7. 9. 10. Chloride 10cc sample of plating solution, dilute to 10000 Acidify with H25304 (1‘5) (litmus) and add 500 excess Add 2 gm. dry sodium perborate After perborate has dissolved add sufficient NaOH solution to make solution strongly alkaline (litmus). Boil for 10-15 min. to decompose excess perborate. Cool to room temperature and add about 1 gm. KI After solution of KI-acidify with st04 (1-5) (litmus) Allow to stand and stir until precipitate is completely dis- solved.“ If the subsequent titration is attempted before the slow reaction liberating iodine is complete, the results will be low. After ppt. is all dissolved titrate with Na28203 solution and starch indicator. (cc .1 N Na28203) (.375) 3 02.00804.7H20/ga1. Same as white nickel Page No. 33 38 IV. Boric Acid A. B. Solutions 1. 2. From cresol purple (.04%) alcoholic Sodium hydroxide .1 N Procedure 1. 4. 500 sample, add 2500 glycerine and 2500 water Add 100 (.04%) brom cresol purple Titrate with standard NaOH solution to dark green then purple (co .1 N NaOH) (.166) 3 HSPOS/gal. V. Formaldehyde A. B. Solutions 1. 2. Sodium bisulphite (1%) Iodine solution .1 N. Dissolve 20-25 gm. KI and 13 gm. 12 in 1 L. water. Standardize against standard Nazszos. 3. Normality 12 soln. : (cc NanSQQS) (Normality N25203) 1:,(00 12 soln.) Procedure 1. 1000 sample plating solution dilute to 5000 2. Add exactly 1000 of the bisulphite solution and allow mix- ture to stand 15 minutes. Tightly stoppered in iodine flask. 'While above is standing pipette another exact 1000 sample of the bisulphite solution to another flask. I Dilute to 5000 and titrate with standard iodine solution ( .l N) and starch indicator to first blue color Titrate the mixture (step 2) in exactly the same way (00 12 .1 N step 4)-(cc 12 .1 N step 5) : 00 12 .1 N equivalent to ECHO in sample (00 .1 N 12) (.05) = oz./gal. 40% HCHO in solution 39 VI. Sodium Formate A. Solutions 1. Sodium formats std. exactly 27.5 gm/L 2. Sulphuric acid (std.) (N) 4 gm./l Standardize as on Page No. Procedure 1. 5co sample of nickel solution dilute to exactly 100cc 2. Add with pipette exactly 5cc normal H2804 and exactly 5cc standard sodium formate solution 3. The electrometric pH should now be 2.7 (-.294 mv. 25°C quinhydrone) 4. If the pH of the mixture is below 2.7 titrate with sodium form- ate to this pH . 5. The number of cc of standard sodium formats used is the number of oz./ga1. required to bring the solution up to the prOper analysis of 5 oz./gal. ' VII. Ammonium Sulphate A. B. Solution 1. Sulphuric acid (1-5) 2. Sulphuric acid .1 N standardize as on Page No. 18 3. Sodium hydroxide .1 N standardize as on Page No. 47 4. Brom cresol purple (.O4%) Procedure 1. 10cc plating solution dilute to 150cc in a 300cc Kjeldahl flask 2. Acidify with dilute H2804, add See excess 3. Add 2 gm. dry sodium perborate, dissolve 4. Put in flask several small pieces broken porcelain, add 3 gm. NaOH pellets 5. Place the distillation trap in position quickly and connect with adapter which dips into a 600cc beaker containing 300cc 8. 10. 40 water and 25cc .1 N sulphuric acid. The end of the adaptor must dip below the surface of the liquid to prevent loss of ammonia. Distill until the volume of solution in the Kjedahl flask is reduced to approximately 100cc When distillation is over, remove trap from condenser and flush out with distilled water. All washings go into beaker Add lcc of brom cresol purple indicator, and titrate with .1 N NaOH until indicator changes color. (cc .1 N H2504used)-(cc .1 N NaOH used) cc .1 N H2804 equiv- alent to RES (.088) (cc .lN H2804 equivalent to NBS) OZ. (NH4)2 SO4/gal. 1. Silver A. B. 41 PROCEDURE FOR SILVER SOLUTIONS Solutions 1. NH4CNS 1/3 N app. a. weigh 22 gr. (app.) NH4CNS, make up to 1 L. b. Weigh (accurately) about .5 gr. pure silver c. Dissolve in 5cc CP HKOS and a few drops of water d. Dilute to 150cc add a few drops of 1Q% Fe(N03)3 e. Titrate with NH4CFS to a faint red color f. Wt. sample 3 gr. Ag/tc NH4CNS solution (factor) (6o NH4CNS used Analysis 1. lOcc of silver plating solution, dilute to 50cc 2. Heat gently, add excess (10cc) of (NH4)ZS, continue heating for few minutes. Stir several times, do not boil 3. Filter and wash with hot water 4. Place ppt. and paper in beaker, dissolve in H1303 (7cc), 5. 6. boil to expell N02 Dilute to 150cc (H20), add Fe(N03)3, titrate as above (cc NH4CNS) (factor) (12.2) - oz. T. Ag/gal. II. Free Cyanide A. B. Solutions 1. AgNOS - .1 N exactly 17 gm./L. Procedure 1. Sec plating solution, dilute to 150cc 2. Add few drops KI solution 3. Titrate with AgNO3 to faint cloud 4. (cc AgNOS) (.2614) : oz. NaCN/gal. 42 III. Carbonate A. B. Solutions 1. N/% H01 ) ) Standardize as in acid copper Page No. 16 2. N/% NaOH) Analysis 1. 5cc sample, dilute to 100cc with boiling water 2. 3. 4. 5. Add excess (20cc) Barium Chloride solution (10%) Filter ppt., Wash thoroughly with hot water Dissolve ppt. in excess acid, let stand 10 min. Titrate excess acid with standard alkali (oe HOI‘used)-(BCI equiv. of NaOH) 3 cc HCI used (co HCl) (factor) (26.8) 2 oz. NaZCO3/gal. lcc N/io H01 : .00531 gr. Nazco3 IV. Chloride A. B. Solutions 1. 1-1 Nitric acid Analysis 1. 3. Boil 5cc solution with 2500 1-1 HNO3 under hood until no further decomposition occurs, cool, dilute to 100cc. Add AgNO3 until chlorides are completely precipitated. Filter on weighed gooch, wash. Pry at 110-11500 to constant wt. Wt. Agcl x 10.76 - oz. NaCl/gal. 43 DETERHINATION 0F MERCUFY IN BLUE DIP I. Mercury A. Solutions 1. NH4CNS as used for silver determination, Page No. 41 diluted exactly 1-10 ( .02N) 2. Ferric nitrate indicator, acidified with boiled 111:0:5 B. Procedure 1. 25cc of plating solution 2. Add 10cc H2804 (caution) to destroy cyanide in solution 3. Add .5 gr. KMn04, heat to fumes, add oxalic acid until solution becomes colorless 4. Beat to fumes again, c001, dilute to 100cc 5. Titrate with unless (1-10) and 10cc Ferric nitrate indicator to first red cloud after white cloud and needle crystals. 6. (cc diluted solution) (factor for Ag of undiluted reagent) (.499) : oz. Hg/gal. II. Free Cyanide A. Same as silver Page No. 41 Factor .1307 (100c sample) I. II. III. Gold 44 PROCEDURE FOR GOLD SOLUTIONS A. Procedure 1. 2. 3. 7. 8. 9. Take 500c sample of plating solution, heat, add 3 gr. NaCN, dissolve, heat gently Add excess pure zinc dust to ppt. gold, stir well, let stand for five hours or over night Wash thoroughly to remove cyanide (decant) Add excess HCl to remove zinc, decant Wash until free from chlorides _ Add concentrated HNO to remove other impurities 3 'Wash, filter, wash Ignite paper in weighed crucible, weigh (wt.) (48.8) = dwt. Au/gal. Free Cyanide A. Procedure 1. 2. 3. Take 10cc sample, dilute to 10000 Add few drops of K1, titrate with lOON AgN03 (co AgNCs) (.01307) : oz. NaCN/gal. Gold (Optional) A. Solutions 1. Na28203 .01 N a. 2.5 gr./1 b. ‘Weigh app. .05 gm. Au, dissolve in aqua regia (10cc) 0. Carefully exaporate to a syrup over a water bath d. Add 1500o water, 5 gr. KI, and starch solution e. Titrate with .01 N NaZSZO3 to disappearance of blue color f. (wt. Au) : factor (cc Na28203)_ 45 B. Procedure 1. 2. 3. 5. 10cc plating solution Add 15cc HCl (under hood), evaporate to a syrup over a water bath Add 1500c water, 5 gr. KI, and starch solution Titrate with N/lOO NazSZO to disappearance of all color 3 (cc 11.125203) (factor) (244) -.-_ dwt./gal. Note - A dilute iodine solution N/lOO may be used to back titrate if necessary. The end point of the NaZSZO3 titration is not sharp, therefore it is desirable to dryness or the gold will be precipitated. 46 PROCEDURE OF DETERMINING ACIDITY OF DEGREASERS I. Acid A. Solutions 1. N/lO Hcl Standardize as on Page No. 47 2. Methyl Orange indicator B. Procedure 1. Filter solvent through gooch if very dirty. Pipette 100cc sample into separatory funnel. Add 1000c water. Add few drops methyl orange 2. Shake vigorously several minutes 3. Draw'off water portion, add methyl orange and titrate with N/lO HCl 4. If the solution turns red when methyl orange is added, this denotes acidity and an unhealthy degreaser condition 5. The titration for a healthy degreaser condition should be run between 1/2 cc and 2-1/ 2 cc N/lO ECl 47 PROCEDURE FOR ALKALINE CLEANERS AND ACID DIPS I. Total Alkali A. E. II. Acid A. B. Solutions 1. NaOH .2 N a. 9 gr. NaOH/L water b. ‘Weigh accurately app. .5 gr. oxalic acid, dissolve in 100cc water 0. Add few drops P. P. solution, titrate with NaOH solution to light red. d. (wt. of oxalic acid) : N of NaOH (vol. used)(2063) 2. H01 .2 N a. 17cc concentrated/L water b. Compare against NaOH solution using P. P. or M. 0. indicator c. _(N of NaOH)(cc used) : N HCl (cc HCl used) Procedure l. 1000 of cleaning solution 2. Add few drops N. 0., dilute to 1000c 3. Titrate'with UCl solution to end point 4. Back titrate with NaCH if necessary 5. 100 1/10 N HCl = .004 gr. NaOH 6. (gr. NaOH) (15.4) : oz./gal. NaOH 7. (oz./gal. NaOH) (1.525) ; oz./gal. Na2C03 Solutions - same as I Procedure 1. Sec acid dip solution 2. Add few drops of N. 0., dilute to 10000 3. Titrate with NaCH solution to color change. Back titrate with HCl if necessary. loo .1 N NaOH : .00490 gr. H280 (gr. H 804) (1.285) : gr. 151:03 2 (gr. H2804) (0745) 2 gr. HCl 4 48 10. 11. 12. l3. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 49 FACTORS (N) (cc) : (N) (cc) (N) (gr. eq. wt. ) Z gr./I (gr. NaCH) (1.525) (gr. LaOH) (2.100) .) _ gr. NaHCO3 (gr. NaHCOS) (.476) : NaOH (gr. NaOH) (1.225) = gr. st04 (gr. NaOH) (1.575) = gr. H1703 (gr. NaOH) (.911) : gr. HCl (gr. H2804) (1.286) . gr. H1103 (gr. F2804) (.745) 3 gr. 501 (gr. Pure St.) : Normality (V01.)I(Mill. Eq. Wt. of St.) (gr./L) (.134) _ oz./gal. (rr./1) (.122) oz. T./%al. (gr./l) (2.44) _ dwt./gal. (Sp: Gr. of Metal) ; oz./sq. ft. for .001" 12 1 02. av. : 28.35 gr. 1 oz. T. : 31.10 gr. 1 qt. = .946 L (gr. AgNOS) (.635) : gr. Ag (gr. KCN) (.755 : gr. NaCN (lcc N/lO NaZSZOE) = .00636 gm. 0o 1cc N/lo Kltno4 : .005584 gm. Fe lcc s/io .MnC4 : .006003 gm. Sb (rg2P207) (.2184) = Mg (r529207) (2.12138) : M5804.7H20 (cc NaOH N/lo) (.0049) : gr. H2804 1600 H2804 : 1 02. Wt. 50 ANALYTICAL SCHEDULES The following is a condensed schedule of routine analytical solution control work. The intervals between analyses have been established by individual solution performance and use. The chart is given only to show'how the schedule was set up in this case, not to be indicative of the frequency analyses might be necessary in other shOps, even those us- ing the same solutions. The chart is set up for a period of one month. Bonday All alkaline clean- ers for P&L alkalin- ity, surface tension and Feaume First Acid dips Week Caustic dips tercury solutions Boiler water Same as first week Second Week Same as first week Third Week Same as first week Fourth Week Tuesday Electroforming solutions All copper sol- utions All degreasers for stabiliza- tion Check all heating coils for leaks Cold nickel sol- utions for pH only Electroforming solutions Copper solutions for cyanide All nickel sol- utions except bright nickel All degreasers for stabiliza- tion Check all heating coils for leaks Electroforming solutions Copper solutions for cyanide Bright nickel Fright 00pper All degreasers for stabiliza- tion Check all heating coils for leaks Electroforming solutions Copper solutions for cyanide Degreasers for Brass solution Zinc solution Check all heating coils for leaks 51 Wednesday Boiler water Boiler water Boiler water Boiler water Thursday Blectroforming solutions First Week Electroforming solutions Second Week Electroforming solutions Third Week Electroforming solutions Fourth Week Friday Silver solutions Boiler water Silver solutions Silver recovery solutions Boiler water Silver solutions Boiler water Silver solutions Boiler'water Pisoellanious Every day pH on Barrel nickel Bright nickel Conveyer nickel strike Three months Carbonates on all cyanide plating solutions Rochelle salts on all cyanide copper solutions Keep following solutions prepared at all times Cadmium brightener for barrel nickel Carbon disulphide brightener for sil- ver Mercury solution Once monthly at end of month gold solutions 53 BRIGHT NICKEL Investigation of Processes In 1937 bright nickel seemed to be well enough established as a re- liable commercial process to warrant thorough investigation as to its possibilities in band instrument work. There were at that time two basic processis for producing heavy bright deposits (19) of nickel, that covered by the Schlotter patent, and that covered by the Weisberg-Stoddard patent. (so) (61) (62) The Schlotter solution was a modified hot Watts solution wherein the brightening agents were furnished in a concentrate form and no good scheme of analysis had been worked out for them at that time. The plater Operat- ing such a solution had no knowledge of the ingredients of the brighteners and in case of trouble often had to depend on service men to find and cor- rect the difficulty. The plate was truly bright although inclined to be brittle and difficultly buffed when buffing was necessary. The Wiesberg-Stoddard solution was a process in which the codeposition of nickel and cobalt (71) was employed. All of the solution ingredients were known and rapid analytical schemes were worked out for the plater. Trouble could be looked for and found by individuals responsible for plating. The plate produced by this process was truly bright. It was not only harder than either the conventional cold nickel deposit or the hot Watts nickel deposit but was also very tough and could be easily buffed when necessary. The solution was more susceptible to impurities than the Schlotter solution, but could be easily purified. The solution worked best using greater agitation than the Schlotter solution but the permiss- ible current density range was adder. Both the initial cost and running expense for royalities and anodes were higher than with the Schlotter solution. It was decided, however, that if a bright nickel process was to be used 54 at all that it should run as trouble free as possible and that it was essential to be able to analyze for all ingredients. If a savings was to be realized it should be sufficient to make slightly higher solution and Operating costs be a negligible item. It was accordingly decided to install the Weisberg-Stoddard process. This did not necessarily mean that this particular process was superior to the other. It only meant that for our own application of bright nic- kel it was believed to be better. Equipment The equipment necessary for a six hundred gallon solution was as follows: 1. l-rubber lined steel tank 84" X 42" 2. 3-1" anode rails 90" long 3. 2-Nelson patent cathode rails 4. l-rubber covered steel center anode rod support 5. 1-800 ampere rheostat 6. 1-60 gal. purification tank 7. l-low speed A150p stirrer 8. l-duriron pump 9. l-industrial 14" X 28" filter, duriron and rubber throughout 10. l-motorized valve and thermostat 11. 55-Cobolt—nicke1 anodes 12. Rubber pipe for air agitation 13. l-duriron heat exchanger Racking The greatest part of the development work was proper racking to avoid shading of parts. Due to the high current density used the racks had to be made of heavier metal. In order to save metal they were covered with 55 rack coating material except at the contact points. A rack material which was found to be highly satisfactory was Korolac, a c0p01ymer vinyl resin. The procedure developed for rack coating was to grind or otherwise remove all sharp corners, apply one coat by dipping, wrap tightly with narrow bias cotton tape, and apply three or four coats over the tape. This procedure was later extended to include all other racks used in plating. Savings After the process had been used for some time and had been adapted to substantially all nickel plating Operations on brass and steel the following observations were made. I The nickel buffing operations had been cut from five full time operators to one Operator working about half time together with one low priced oper- ator to wipe water marks and to fan slight clouds sometimes unavoidably ob- tained. Savings were made on every part processed. These savings graded down from a high of twenty cents a piece for bugle lyra frames, representing four hundred dollars per year on this part only, to a few cents per hundred for very small parts. In addition to the above savings a destinct increase in quality was ob~ tained. The plated work was blue white in color instead of a yellow white and had a greater resistance to tarnish than the conventional nickel de- posits. In buffing very angular and deeply recessed band instrument parts there always had been trouble in cutting through, the sharp corners. When- ever some pieces were cut through, the rest were always very thin at those points which resulted in earlier breakdown than if no metal had been re- moved by buffing. This trouble was completely eliminated with bright nickel and resulted in savings difficult to estimate, but nevertheless real, in customer good will and in the lowering of complaints. The nickel plating rates also were lowered partly due to the speed the 56 operator could plate the work and partly due to a rearrangement of the plating room which resulted in about thirty steps taken per batch of work or about eighty less steps than previously. Due to the speed nickel could be plated from the bright nickel solution several old solutions were dis— carded which greatly cut down analysis and maintenance expenses. The extra expense involved was a higher price of anodes which amounted to about five hundred dollars per year for the first three years and there- after was cut to amount to about two hundred dollars per year. This ex- pense was well justified in view of the savings realized. Purification Two methods of solution purification (53) were successfully used, the chemical purification and the electrochemical purification. The chemical (37) purification, or Lipscomb purification, was performed as follows: 1. Raise pH to 6.4 - 6.5 colorimetric 2. Heat to 150°? 3. Add 1/4 lb. ferrous sulphate per 100 gal. of solution, and stir thoroughly 4. Add 1 pt. of 100 volume hydrOgen peroxide per 100 gal. of solution 5. Allow to stand at 150°F with constant stirring for at least six hours 6. Filter out suspended matter 7. Heat filtrate to 160°F with stirring for one hour to release peroxide 8. Adjust pH to operating range. 9. Lead, zinc, tin, iron, and copper is removed This method had the advantage that it removed all impurities rather completely. It had the disadvantage of being rather time consuming. The 57 solution was out of production while being purified and at times was some- what irratic when first placed back in service. The electrochemical (63) purification method was continuous and when used in conjunction with pr0per filter procedure was far more satisfactory. The solution which was continuously filtered was returned through a puri- fication tank of about one tenth the capacity of the plating tank. This tank was equipped with nickel anodes and cathodes of sheet brass or steel. The cathode area was as large as was possible to get in that size tank. A fixed resistance allowed current to pass during plating operations at the rate of two or three amperes per square foot. At this current density impurities such as lead, tin, iron, and copper were plated out on the cath- odes in a much higher proportion to nickel than at the higher current den- sities at which bright nickel was plated. It was found that a solution may be kept substantially free from these metallic impurities in that way even though deeply recessed work with soft soldered seams was being plated. At times when the purification unit was inadaquate the main plating solu- tion was dummied in the same way during off hours. All organic contamina- tion encountered in over three years of operation was removed in the filter (1) (9) (41) proper by a mixture of activated carbon (26) and activated clay. In operation the filter plates were precoated with a diatomaceous earth (42) hyflo, one third superfiltro, an activated clay, and one third darco, an activated carbon. It was found that recharging the filter every two ‘weeks was sufficient to maintain flow rates and to keep the solution free from organic impurities. Again, this was a specific case and might not be often enough in some solutions under some conditions. 58 Solution Composition The nOminal solution composition and the function of each ingredient is as follows: Ingredient Amount Function NiSO4.7H20 52 oz./gal. To furnish metal hi012.6H20 6 oz./gal. To promote anode corrosion To furnish metal C0804.7H20 2 oz./gal. Ni(OOCH)2 6 oz./%e1. ) or FaOOch 5 oz./gal. ) Puffer, brightener or HCOOP 3 oz./ga1. ) H3B03 4 oz./gal. Regulates pH of cath- ode film, permits higher current density (NH4)ZSO4 .33 oz./gal. Gives depth of color HCHO .33 oz./%al. Activates brightening influence of formats 59 Operating Conditions The solution analysis, operating conditions and permissible variations are as follows: Ingredient Amount Permissible Variation Ni 8.6 oz./ga1. 7.0 oz./ga1. up NiClZ.6H20 6.0 oz./gal. 3.3 to 6.5 oz./gal. 00804.7H20 2.0 oz./gal. .5 to 3 oz./ga1. HCOONa 5.0 oz./%al. l oz./%al. up (NH4)ZSO4 .33 oz./gal. .2 to .7 oz./gal. HCHO .33 oz./gal. .25 oz./gal. up pH 3.7 electrometric 3.6 to 3.9 Current density 40 amp./sq.ft. 10 to 100 amp./hq.ft. Temperature 60°C 550C to 65°C Agitation Air Rapid cathode oscillation 60 In some cases there could be wider variations than noted above, however, trouble in one way or another was apt to be encountered. It was found that the presence of sodium salts induces harder deposits. Nickel formats was accordingly used for additions instead of sodium formats, and formic acid was used to lower pH. When necessary, nickel hydroxide or carbonate was used to raise the pH, thus avoiding further additions of sodium salts. BARREL NICKEL PLATING A study of Figure No. 1 shows that in 1935 the barrel plating operations (8) were scattered all over the plating room. This had an effec of slowing production, as well as making the work difficult for the Operator. At this time barrel nickel work produced was not entirely satisfactory in appearance and there were also numerous complaints due to an early break- down of the finish. Increases in sales also made necessary increases in production facilities. Equipment The problem of advantageously grouping the equipment was first attacked. At the same time the bright nickel was installed a complete plating room arrangement was made, whereby all barrel plating equipment was moved to one end of the plating room and segregated by a partition. This part- ition was erected primarily to keep flying drying compound from settling in other solutions. The grouping of the equipment cut down the operator's steps from one hundred ninety to eighty per load of work. The new'equipment found necessary was to replace the old single barrel plater'with a new modern double barrel plater. An additional burnishing barrel was also purchased. A study was made to determine the prOper barrel speed for each type of piece. The burnishing balls, cones, and stars were found to be badly rusted, shipped, and broken, which resulted in scratbhes on the work. NeW'burnishing material was provided to replace worn out 61 and inadaquate material, thus the appearance of the work was improved. Old Procedure It was found that the rusting of barrel nickel plated parts was due to both inadaquate thicknesses of nickel and to improper application of metal. The old barrel nickel plating procedure was as follows: 1. 2. Sand or punics tumble, where necessary, 12 to 48 hrs. Ball burnish 1 hr. to 40 hrs., depending on finish, in neutral soap solution (40) Clean in baskets by oscillating up and down in hot alkaline cleaner for l min. Rinse (Pickle in 1-1 HCl solution for 30 sec. Rinse Farrel nickel plate in following solution Ni - 3 to 4.5 oz./ge1. NaCl - 3 oz./ga1. H3B03 - 3 oz./gal. pH - 6.0 to 6.2 colorimetric Temperature - room Time - 20 to 30 min. Current - 30 to 50 amp./load Often the above cleaning procedure did not properly clean the work (34) before plating. The work picked up dirt, grease, and insbluble calcium and magnesium soap films from dirty barrels and dirty burnishing balls. An extreme effort was made to clean up the barrels and balls and to keep them that way by carefully cleaning the work before burnishing in a three phase degreaser, using stabilized trichlarethylene solvent followed by an alkaline cleaning. It was found that insoluble soap films could largely 62 be avoided by incorporating a small amount of a sulphonated alcohol (25) (43) (51) called orvus in both the cleaner and the burnishing soap. Small quantities of orvus amounting to about one half of one percent of the weight of the other cleaning compounds was found to be sufficient. New Procedure The nickel solution was changed to a hot solution, higher in metal, with a higher permissible current density. The time of plating was also increased. The operating pH of the solution was lowered to prevent the codeposition of basic nickel compounds with nickel. Drying methods after plating were also inprovsd by substituting corn bob meal for sawdust in drying the work. Sawdust had a tendency to sour and become soggy much quicker than the corn cob meal. These advantages compensated for the slightly higher cost of the meal. The plating procedure as revised was as follows: 1. Degrease (58) (69) 2. Clean in hot alkaline cleaner by oscillating by hand 3. Sand or pumice tumble 12 to 48 hrs. 4. Ball burnish l to 40 hrs. depending on finish in neutral soap and orvus 5. Clean in hot alkaline cleaner 6. Rinse 7. Pickle in 1-1 HCl solution for 30 sec. 8. Rinse 9. Barrel nickel plate in following solution Nickel Natal - 6.5 to 7 oz./ga1. Chloride as nickel chloride - 4 to 5 oz./gal. Poric acid - 4 oz./gal. pH - 5.8 mas. (colorimetric) Temperature - 45° to 50°C 63 Time - 1 hr. Current - 75 to 100 amp./load Size of load was about one third more than in old method. Summary of Improvements The following is a brief summary of the improvements made on barrel nickel plating operations: 1. 2. 9. 10. 11. Advantageous grouping of equipment Purchase of properly designed new equipment Erection of a partition to prevent contamination of the other solutions Reduction in operator's effort of one hundred ten steps per load Adjustment of burnishing barrel speed Provision of proper burnishing materials Elimination of grease, dirt and insoluble soap formation from process Elimination of broken or chipped materials Modification of plating solution to provide much greater thicknesses of nickel and increase permissible loads Use of a degreaser Use of better drying material PLATING ZINC ALLOY DIE CASTINGS A great deal has been written of the plating of zinc alloy die castings. (3) (4) (57) A large number of procedures have been recommended. All proced- ures and recommendations were carefully studied and most of them tried, at least experimentally, in a search for the highest quality at the lowest cost. A rather complete report of our work on die cast plating is given here. Possible Plating Cycles There are three generally accepted schemes for applying nickel deposits 64 to die castings, each of which has a number of variations. The three systems may be called the nickel direct system, the copper-nickel system, and the nickel-copper-nickel system. All three systems are satisfactory from a corrosion standpoint if the layers of cOpper plus nickel are of equal thicknesses and are properly applied in all three cases. There seems to be little difference between the corrosion resistance of .001" of prOperly applied nickel alone and an agregate of the same thickness of cOpper plus nickel. It is difficult, however, to obtain a thickness of nickel directly over zinc to meet specification plating for outdoor exposure without running the danger of brittle deposits from the cold, high sulphate nickel solutions from which they are plated. With high sul- phate solutions the common sulphate ion provided by sodium or magnesium sulphate reduces the tendency of nickel to deposit by immersion in black spongy deposits by reducing the nickel ion concentration. Even if this precaution is taken there is always danger of deposition by immersion in recesses where the current cannot throw nickel, or where the current density is low; fin added difficulty is that during this deposition an equivalent amount of zinc is dissolved by the solution. Zinc in nickel solutions rapidly poisons them making necessary purification or a new solution, both of which are expensive and time consuming. The copper-nickel system eliminates the necessity of high sulphate nickel solutions and permits the use of conventional warm or bright high speed nickel processes. This system also minimizes the danger of crack- ing of the plate and to a large extent prevents solution contamination by zinc. The major objection to this method is that the thickness of copper next to the die cast base metal must be at least .0002" thick after the buffing Operation. With less copper than this minimum thickness the absorbtion of the copper by the zinc to form hard and brittle cOpper-zinc 65 alloys in the beta and gamma ranges, increases the danger of peeling as the absorption layer approaches the nickel plate. A die casting is con- sidsrsd immune to this defect if the copper deposit is at least .002" thick at its thinnest point. The cOpper absorption undoubtedly continues during the life of the part but the rate apparently slows down to a neg- ligible value after a short time. The difficulty is to apply enough cOpper to irregularly shaped Objects so that the Operator doing the buff- ing leaves at least the minimum required thickness. Another draw back to this method is the additional expense of plating and buffing the copper deposit. The nickel-copper-nickel system.ninimizes the difficulties encountered in both the above systems in that a thin coating of nickel, not enough to crack or check, is first applied in a high sulphate solution, then as much copper as necessary to prOperly buff. After buffing a finish coating of nickel from any standard solution may be applied. This method is considered best from the standpoint of quality and service but is seldom used because of the comparatively high labor and solution cost, therefore it will not be considered further in this discussion. Preplate Treatment The plating procedure for zinc alloy castings before work was started to improve the process was given on Page NO. 6 That procedure in the light of present day knowledge has many Obvious flaws. These will be taken up in the order they were attacked. Cleaning was first studied. Many proprietary cleaners were tried and some used successfully. It was found, however, that a cleaning solution (34) made up using 3 oz./%al. NagPO4 and 3 oz. gal. NaZCO3 to which was added 1/2 pt./’ 100 gal. of a sulphonated alcohol called orvus (51) was as successful as any tried and a great deal cheaper. It was also found that wiping could be eliminated by degreasing the parts properly in a three phase trichlorethylens 66 degreaser (29) (58) (69) before alkaline cleaning and that the time of clean- ing could be greatly reduced. In this connection it was found that over cleaning produced as many or more rejects as under cleaning. (2) An acid dipping technique was successfully used wherein the work was immersed in a hydrochloric acid solution containing nickel sulphate com- pounded in the following proportions: HCl - 1.5% by wt. NiSO4.7H20 - 10 oz./ga1. The first dip produced a deposit of nickel on the zinc alloy by immersion. The acid undercut the surface through porosity in the immersion deposited nickel which left shallow pits to which subsequent deposit mechanically interlocked. Obviously, the undercutting operation could not either be too shallow or too deep or an inferior finish would be produced. Copper Plating The copper plating operation was modified several times. The use Of acid copper was early abandoned due to the severe attack of the zinc by the acid in deep recesses. For a time a Rochelle copper deposit (21) was produced upon which nickel was plated without the preliminary OOpper buff- ing. It was difficult to hold an order of smoothness sufficient to finish and at times great difficulty was encountered in nickel buffing. Bright copper was installed as soon as enough knowledge was available. This was done by first applying a thin strike or flash of Rochelle 00pper and then plating to thickness in a Greenspan bright OOpper solution. (24) (23) Nickel Plating Bright nickel was used directly over the above bright copper deposit as soon as bright nickel was available. By plating bright nickel over unbuffed copper one Of the major objections to the copper-nickel system was eliminated. No copper was removed by Buffing and minimum thicknesses Of copper were much easier to maintain. The deposit of bright copper- 67 bright nickel were often smooth enough that a wiping operation to remove watermarks was all that was required. It was found, however, that a fan- ning operation using a soft wheel and rouge was as cheap as wiping and also removed slight clouds sometimes produced in the compound deposits. Revised Procedure The final plating sequence established for zinc alloy die castings was as follows: 1. Pegrease - Three phase degreaser 2. Rack 3. Soak clean NagCO3 - 3 oz./ga1. Na3PO4 - 3 oz./ga1. Orvus - 1/2 pt./lOO gal. Temperature - 180°? - 212°F Time - 15 sec. 4. Cathodically clean Same solution Time - 15 sec. 5. Rinse 6. Nickel acid dip ECl - 1.5% by wt. NiC12.7H o - 10 oz./gal. 2 Time - 3 sec. Temperature - room 7. Rinse 8. Rochelle copper strike Time - 3 min. Temperature - 50° - 55°C Tank potential - 4 volts 9. Rinse 10. Rinse 11. Bright copper plate Formula on Page No. 70 Temperature - 60°C Time - 17 min. Current density - 30-40 amp./sq.ft. Tank potential - 2 1/2 to 4 volts 12. Pinse 13. Acid dip 1.5-21 HCl by wt. Time - 2-3 sec. 14. Rinse 15. Bright nickel plate Formula on Page No. 59 Temperature - 60°C Time - 15 min. Tank potential - 3 volts 16. Rinse 17. Hot rinse 18. Unrack 19. Nickel fan Comparison of Costs and Quality In order to get a comparison of costs before and after the above developments one part was taken as a fair example. The corplete finish- ing cost for labor and overhead before the above changes were made was eight dollars per one hundred parts. The cost after the process was im- proved for the same one hundred parts was seven dollars. This saving was made over a period when wages went up about twenty percent. The 68 69 changes definitely improved the quality in several ways. The rejects from peeling and blistering were greatly reduced. Due to the fact that copper was not buffed at all no metal was removed in this operation and minimum thicknesses were easily maintained. Little nickel was removed in the fanning operation after plating and few, if any, losses are realized from cutting through the deposit on sharp corners. More nickel was applied and the harder bright nickel deposit was found to be less por- ous and more resistant to corrosion. BRIGHT COPPER Processes Available During the die casting problem the necessity of a bright copper solu- tion.was realized. There were at that time only two commercial bright copper processes known to the author. These were the Zialite process (5) and the duPont process. (46) Experimental solutions of both processes were installed and Operated. The Zialite process was found to have too low'a limiting current density to be useful for this application. The duPont process was successful but for two outstanding faults difficult to elim- inate. Burning on the high current density areas was very pronounced if the limiting current density was only slightly exceeded. The greatest trouble was realized from roughness of the deposit even if electrolytic anodes were used. The maximum brightness obtainable in steady operation 1 was also not believed to be sufficient for this application. It was learned that Greenspan and Weisberg had been working on a bright 1 The author's opinion on any propriatary process discussed in this paper is only in respect to the specific application in which it was tried and should not influence the reader in any way as to its usefulness for any other application or to the industry in general. 70 copper process and had it developed to the place where it was ready for commercial trials. An agreement was reached whereby the development work was to be done in our plant under production conditions on zinc alloy die castings. (23) (24) Amine Bright Copper The formula submitted as the best found in the laboratory was as follows: Cepper sulphate - 13.5 oz./gal. I Ammonium sulphate - 2.75 oz./gal Diethylene Triamine - ll/b oz./gal. Ammonia - 4.5 fl. oz./gal. Tergatol penetrant 03 - .25 oz./gal. It was found that neither iron nor lead lined tanks were suitable. A three hundred gallon solution was therefore prepared in a rubber lined steel tank. The tank was equiped with a cathode rocker which had a four inch stroke with twenty four cycles per minute. A nickel silver heating coil was used which in Operation was made slightly cathodic through a suitable resistance to prevent stray fields from corroding the coil and starting leaks. The anodes wmre conventional rolled copper anodes. A filter was provided and was tried both with constant and intermittent filtration. Periodic filtrations were found to be suitable. Deve10pment Work The experimental work on bright copper consisted of studying the fol- lowing factors: Cleaning methods, acid dipping, procedures, Rochelle cepper strike, all operating conditions such as current density, tempera- ture, filtration, agitation, and bath composition, the subsequent bright nickel plating conditions, and drying methods. In all, about eighty trials were made before production runs were started. Observations on each variable were made and recorded. These observa- tions follOW’in a condensed form. The cleaning and preplate cycle as out- 71 lined in the above procedure under zinc alloy die castings must be c10$ely followed to avoid trouble. The time of the Rochelle strike is important and must be at least two minutes to completely cover the die casting. The solution concentration may vary over rather wide limits and still produce bright deposits. The ammonia content may vary widely with no de- trimental effect, however, with low ammonia it is necessary to use greater agitation. A high ammonia content permits higher current densities. The copper‘concentration is not critical. The solution has been successfully operated from one half to twice the nominal copper content. However, the ratio of the cOpper to sulphate should be rather closely maintained for very bright deposits. The temperature can be varied from 450C to 75°C and except for the fact that the higher temperatures permit higher current densities in the bright range, bright plates may be secured within the above limits. The maximum and minimum permissible current density is determined by the variables of temperature, ammonia content, racking and agitation. Brilliant deposits can be produced between 10 amperes per square foot and 130 amperes per square foot. The optimum range is between 40 and 70 amp- eres per square foot for the general run of work. Fitting was the trouble most frequently encountered. Filtering through diatomaceous earth frequently helped. The use of willow charcoal and activated clay in filtering along with the filter aid was also found to be valuable. Additions of the wetting agent also helped. Adjustment of copper to sulphate ratio was found to be important to suppress pitting. Dull deposits and roughness always were overcome by the addition of ammonia or amine if the racking and solution filtration had been properly carried out. The bright copper process has been singularly successful over long time heavy production. A substantial part of the savings and increase 72 in quality realized in the above die casting problem was due to its success. BATON STAFF PROBLEM Busting This problem and its solution is described here because it is a typical case of one of many problems encountered in plating room practice not in- volving a change in plating procedures. It often happens, as in this case, that a change in material solves a serious problem. Baton staffs were made from a tube of .750" X .680" X 28-3/4" long steel into which were soldered two end plugs, one solid, and one hollow. The hollow plug was threaded on the inside to receive a baton ball. These staffs were polished, bright nickel plated and chromium plated. Many complaints were received from the trade due to rusting of the in- side of the staff which weakened it to the extent that it easily fractured when drOpped or otherwise abused. This rusting was traced to the process- ing solutions which removed protective grease and scale films from the in- side of the staffs and perhaps left residual chemicals and moisture. The following modifications in procedure were unsuccessfully tried to eliminate the trouble. 1. Building racks vented to above the surface of the solutions to equalize the internal pressure in the staffs and to pre- vent the entry of solutions into them by the partial vacuum otherwise created when the work was transferred from a hot to a cold solution. 2. Carefully drying out the inside after plating with alcohol and air. 3. Coating the inside of the staffs with beeswax dissolved in carbon tetrachloride. 4. Coating the inside of the staffs with rust proof oil. 73 Change in Material None of the above efforts eliminated the rusting difficulty and com- plaints were nearly as numerous as before. An investigation was carried out to determine the possibility of a more corrosion resistant material. After many trials it was found that very hard drawn nickel silver, containing 15% nickel, was strong enough even though a thinner wall stock had to be used to obtain the same weight. The weight factor was very inportant in this particular instance. The nickel silver was a much more expensive material. Consequently a study of possible processing changes was made to approximate, if possible, the same production cost as when steel tubing was used. The oiling, some of the polishing operations, water testing for leaks, drying with alcbhol and air, and nickel buffing could be eliminated by using nickel silver. Other Operations could be minimized due to the superior finish of nickel silver atd its better workability. The net savings in labor and overhead effected by the use of nickel silver per 100 staffs was $15.24. The added material cost was $17.20 per 100 staffs. This left an increase in cost per 100 staffs of $1.96 or about two cents each which was a very small price to pay for the elimination of a very serious difficulty. Where previously dozens of staffs were returned and had to be replaced before the change in material not a single case has come to the author’s attention in over a year of production of many thousands of the new staffs. AUTOlATIC SILVER PLATING Bright Silver A thorough investigation of silver plating was started which rather thoroughly covered all phases of the subject. The objects of the invest- igation were as follows: (18) (38) (45) (50) (52) 1. To find a more rapid method of depositing silver. 74 2. To find a silver process to produce deposits of mirror brilliance 3. To improve preplate methods to eliminate hand work such as scrubbing 4. To find a method of depositing silver more resistant to severe perspitation conditions. 5. To devise racking technique to replace wiring 6. To conveyerize all operations if possible The subject of bright silver and rapid silver seemed to go hand in hand and were investigated first. A search of patent literature was made. Sev- eral patents were found which claimed addition agents to the regular cyanide- carbonate solution or a modification thereof which would produce bright deposits. Nercaptans, urea, thiourea, thiosemicarbazide, and derivitives of the above compounds were faithfully tried according to instructions. Vary- ing degrees of bright silver was obtained and in some cases brilliant silver was plated. The bright ranges were either too narrow, the limiting current densities too low, or the baths themselves too unstable to be of use in our application. Accordingly work on bright silver was abandoned and work was continued on finding a stable silver solution with a high permissible current density. Many addition agents and many different bath formulations were tested in one and five gallon laboratory solutions. A silver bath was found which cut silver plating time to about one fourth that of previous practice. This bath formula was as follows: (28) (66) Ag - 2.00 to 2.25 oz./ge1. NaCN (free) - 2.3 - 3.0 oz./ga1. m-cog, - 16 oz./gal. Na2C03 - 3 oz./gal. max. (32) (33) 75 Temperature - 30°C - 35°C Agitation - cathode oscillation Current density is not mentioned in the above formula nor will it be mentioned in the following discussion of silver plating, for the same reason as explained on Page F0. 4 Sodium cyanide was used to maintain the cyanide content because of price considerations. Potassium cyanide worked equally as well. Drag out was found to keep the ratio of sodium to potassium salts sufficiently in balance to prevent trouble due to a high sodium salt content. (3o) (55) Cleaning It was found that grease and dirt could be entirely removed from the work by a soak cleaning cycle of six minutes followed by a cathodic elect- ric cleaning cycle of two minutes in a cleaner of the following formulation: NaCH - 50 parts Na2003 - 40 parts NaCL - 25 parts ha3PO4 - 40 parts liaZPO4 - 400 parts. The above mixture was made up 6 oz./hal. and a wetting agent (orvus) (25) was added in the ratio of one pint per one hundred gallons of cleaning solu- tion. The solutions were operated hot (1850 to 210°F). Staining of the brass surface, when it occured, was eliminated by small additions of amnonium chloride. This addition agent, due to hydrolysis slightly, reduced free alkalinity of the solution. (7) (10) (ll) (12) (29) (34) (16) (43) (47) (48) (51) (56) (64) (67) (68) Acid Treatment In the previous silver plating procedure (Page No. 3) hand scrubbing and bright dipping was necessary to insure the removal of dirt, grease, and tarnish. The above alkaline treatment adequately removed the dirt. The 76 next problem was to remove the tarnish, scale, and oxides without bright dipping. A bright dip operation would have been difficult to con- veyerize due to the extremely short immersion time permissible. Bright dip fumes would have been very detrimental to machine parts. The use of a bright dip on horn parts due to rapid metal attack, was also undesirable. After many trials of different acids and acid combinations it was found that a 32° Fe. sulphuric acid solution in which the work was made the cath- ode at 50 to 100 amperes per square foot performed very efficiently. Scale, tarnish, and oxides were removed in a maximum_time of three minutes. In operation, this solution acted as an ordinary acid solution in removing scale chemically. The large quantities of nacent hydrOgen evolved on the work surface reduced oxides to the metallic state electrochemically. The tearing and prying action of the liberated hydrOgen also aided in the removal of loose material. (13) (39) (44) (54) 00pper and Nickel Striking Silver, even in cyanide solutions, has a very decided tendency to de- posit on copper or copper base alloys by simple immersion whereby non- adherent silver deposits are produced and equivalent amounts of the base metal go into solution. This tendency may be overcome or minimized in a number of ways in silver plating copper base alloys. 1. By using a series of silver strikes starting with low silver content and high free cyanide and working up to the plating solution formula. The current density in the strikes must be high and the time must be short. 2. By using a mercury or "blue dip" which deposits a film of mercury on the work. The amalgam formed is said to aid in the adhesion of the silver plate probably because it resists the deposit of silver by immersion and forms a layer of silver amalgam. 77 3. By preplating with nickel upon which silver has little or no tendency to deposit by immersion. The series of silver strikes was undesirable.insofar as conveyerizing was concerned due to the problem of solution control and the number of tanks necessary. The use of mercury on any nonferrous metal is undesirable wherever avoidable due to the fact that mercury actively predisposes sea- son cracking, especially upon thin hard rolled sections predominant in band instruments. A mercury dip was to be avoided if possible also from the standpoint of the very short immersion time difficult to obtain on a full automatic machine. The nickel undercoat was decided upon as the most legical undercoat to use. Tests were run on the corrosion resistance of silver over a thin pore free deposit of nickel using the standard silver plate over brass as a control. The tests were performed by oscillating a test plate at constant load and constant speed over a felt pad which was soaked with a synthetic perspiration of one of the two following formulae: 1. Acid synthetic perspiration Sodium chloride - 2.65 gm./i Urea - .75 gm./I Make pH 5.3 (electrometric) with acetic acid 2. Alkaline synthetic perspiration Ammonium chloride - .839 gm./L Sodium chloride - 1.732 gm./l Ammonium hydroxide sp.gr..88 - .42 cc/l Hake pH 7.5 (electrometric) with acetic acid It was found that with the nickel undercoating the silver resisted cor- rosion nearly twice as long as silver alone with all other conditions the same 0 78 The horns and horn parts which were silver plated were assembled largely with soft solder over which nickel has a well known poor adhes- ion. If nickel were to be used as an undercoating some way had to be found to overcome this difficulty. Two methods were tried. The first was that of using a nickel solution which had been rather extensively used to plate stainless steel. The solution of the followb ing bomposition was also found to be suitable for depositing adherent nickel on soft soldered joints. Nickel chloride - 27 oz./gal. Hydrochloric acid - 16 fl. oz./gal. Current density - 50 to 75 amp./Eq.ft. Temperature - room Time - 1 to 4 min. In use this solution was found to have sufficient throwing power to cover deep recesses. This may have been partly due to the local cell action between the solder and the brass or the constituents thereof which generated a potential sufficient to successfully Oppose the plating poten- tial in recesses. This solution was consequently abandoned although it was perfectly satisfactory in every other respect. (20) (65) The second method used for applying nickel to brass before silver plating was to first apply a copper strike followed by a modified hot Watts nickel. (22) Copper applied from a cyanide solution or Rochelle copper solution was known th adhere well to soft solder as well as to have a high throwing power. (21) (70) The copper strike was also found to have the same distinct advantage of connecting slight imperfections in the pre- vious cleaning steps as in the nickel plating procedure Page No. 9 The formula of the nickel solution used was as follows: NiSO4'.‘ 7H20 - 27 oz./ga1. 79 NiC12.6H o - s oz./gal. 2 H3P03 - 4 oz./aa1. Ngso4 - 5 oz./ga1. pH - 5.8 (colorimetric) rTank potential - 2.5 - 3.5 volts Temperature - 6000 Agitation - Cathode oscillation The magnesium sulphate was added to improve throwing power. Recovery Work was done to find the most efficient way to recover silver from rinse water without the use of elaborate counter flow systems. This proved to be a very simple problem. It was found that if a steel rinse _tank contained a quantity of zinc borings and turnings any silver enter- ing the tank was rapidly and completely deposited on the zinc by immersion. The resultant impure cement silver periodically was sent to a reliable refiner for recovery. (6) (27) (49) Plating Cycle The new silver plating cycle was a follows: 1. Rack 2. Alkaline clean-still 6 min. 3. Alkaline clean-cathodically 2 min. 4. Rinse 5. Electric acid 3 min. 6. Rinse 7. 00pper strike 1 min. 8. Rinse 9. Nickel strike 3 min. 10. Rinse 11. Silver strike 2 min. 80 12. Silver plate 15 min. 13. Recovery 14. Recovery 15. Hot rinse 16. Unrack Pilot Plant Work After the above cycle had been worked out in the laboratory, tolerances and optimum operating conditions established, and corrosion tests perform- ed, a pilot plant was set up to do production work. The complete cycle was carried out using fifty gallon solutions which were prepared in steel drums and stoneware crooks. This plant was sufficiently large to silver plate cornets, trumpets, and metal clarinets as well as smaller parts such as accessories. A total of one thousand horns were plated wherein a complete record was made on each horn of instrument number, method of degreasing, if any, time, terperature, current flow, voltage in.each solution including cleaners, and complete daily analyses of each solution. In this plant minor variations in plating technique, material handling, and solution composition were worked out. It was also in this pilot plant that it was definitely established that it would be practical to convey- erize silver plating operations. No study of racking methods for horns, particularly the larger ones, could be made in the small pilot plant. Also no definite proof could be established that the procedure worked out for the smaller horns would be satisfactory for larger horns such as baritones and sousaphones in respect to throwing power. Another pilot plant was built wherein three hundred gallon solutions were prepared. The same care in recording data was used here as in the previous pilot plant. A total of three thousand band instruments of all sizes were plated which resulted in only minor modifica- tions in plating technique. 81 Racking The racking problem was very carefully studied and sample racks were made for each piece. All racks were made of one half inch round brass rod covered wdth koralac rack coating material and bias cotton tape which was subsequently impregnated with koralac. The koralac was a special. copolyner vinyl resin especially compounded for plating racks and its use was found to be very successful in every plating and cleaning solution except trichlorethylene degreaser solvent. Brass rod was used instead of copper because it was a stock item and did not have to be a special order. It was found to be as good if a sufficiently large size was used to carry the current. ho special racking technique was needed on small horns and parts except to devise ways to obtain approximately the same effective cathode area on each rack. In the cases of the larger horns special anodes had to be used to obtain deposits in recesses sudh as the inside of horn bells and around valve sections. Pure strip nickel was found to be nearly an ideal material as it was substantially insoluble in all processing solu- tions. It was only necessary to use an electrical connection from the special anodes to the positive side of the plating line while the work was in the silver strike solution. In the other solutions, copper strike, nickel strike, and silver plate, the special anodes performed the unique function of bipolarity without direct electrical connection. These anodes in places were rather close to the regular tank anodes.. In the absence of direct electrical connection they were cathodic at these points. At the points where they were close to the horn, that is in the recesses, they were anodic. The electrical resistance in the metal was less than in the solution, therefore considerable current was conducted by them. 82 This is the only application to the author’s knowledge where the well known phenomena of bipolarity has been used in a practical plating room process. Another well known electrochemical application of bipolarity is in the series refining of copper. Conveyerizing A complete study was made of possible savings which might result in an automatic silver plating nachine using the new cycle. An itemized list of the factors considered is given without the specific savings in each case. 1. Labor 22 Frag out (13) 3. Brushes 4. Pumice 5. Sulphuric acid 6. Nitric acid 7. Reclamation charges 8. Increased quality The above study proved that the cost of an automatic machine could easily be justified. The cost could be written off at the rate of about one third per year. Machine The plating machine decided upon was a Hanson-Van Winkle-Eunning elevator type conveyer. The machine was equiped with a hydraulic lift, a hydraulic index, electric timer, and an agitation mechanism which gave variable cath- ode oscillation transverse to the work travel. The machine had an overall length of sixty six feet ten inches, was eight feet wide and eight feet six inches high. The distance between carrier centers was three feet and the lift was four feet. The machine was equiped with forty carriers and at nor- mal operating speed turned out one rack per minute. This could be varied 83 from twenty seconds to three and one half minutes insofar as the machine was concerned but only from one half minute to about two minutes in act- ual practice because of plating specifications. Summary of Silver Developments All of the objects given on Page No. 73 except bright silver were achieved. Costs were cut, quality increased, tine decreased, hand work eliminated, racking developed, and a brighter more easily finished product was obtained. IAYCUT CHANGES Changes from 1935 to 1940 Figures No. 1 and No. 2 have already been explained. Figure No. 1 is a layout of the plating room in 1955. Several changes were made between 1955 and 1940 due to changes in processing already explained in detail and other changes of a less important nature. The following are the layout changes during this period and the general effect on the efficiency of plating room operation. Figure E0. 3 shows the layout in 1940. 1. The control laboratory was moved to a new building on the opposite end of the plating room, was greatly enlarged, and modernized. 2. The ball burnishing, and barrel nickel plating operations were gathered to one location and segregated as already noted with a resultant saving of one hundred ten steps per load. 3. Depreasing systems were installed. (58) (69) 4. Solutions were advantageously grouped so that miscellaneous plating operations, repairing, and stripping was more efficiently performed. 5. Bright nickel was installed subsequently retiring several cold nic- kel solutions. Steps saved in nickel plating were eighty steps per batch. 6. The gold plating solutions were reduced due to less production de- mands. (35) l ! TH } D: H a, |"'- e m: H. L? c ‘52 l—I- .@ ”’93 w m g 2'53} In I BARREL ROOM 2?: IL- ” s Cr 4 a [fig] 1. a [—— s a a a a 104 W PP PP .44: Ml ' 1 0'3 w B a 5 @, x_______w s 02 Cr/ w 5 B a _ m .9 I” c c n’ u w % 69 ‘ Ila I c” _. -_.4 M 495' [4.96 A], .496 5’“, M2 F—' C C . 8r 8,, W W 60/ a 5 av Aw __ _ _ A /o A 9 C / .9 J F Au/ 0 C r{8_ _ 11/3 [bl 4’18 A!” 70 “5* ”/3 W W I I 600/ I IV I g _ _ _. _. I I 6‘8 A? ' ' C 68/? g - BM/ 9 2. 8 -fi r ’ j s ‘9 a a 60 seems/>622 @ 69% ACID ROOM “0 flak/165 é] BUFF ROOM ; . J‘ J 5.7 ' ‘ 4.3 W 1m . ml a a we 0 A * WORK/PACK C ‘ AMA 1. /NE a [AI/YER J‘- a UFF JACK W -fl//v.s‘£ TANK I“ - Paws/71. 7273 FUR/flat now If - KOROLAC 8- WORKAE/VCH 60 ~3Awousr axe/5R ‘\ 6M0 - c VAN/at COPPER 5A 7'// (WI;- Cm/V/ot’ Z/A’C 5A 77/ AC» —/?06//E/.L£ COPPER 5177/ Ach-AC/o Z/A/C EAT/l 8rCu - 58/6/17 cop/>53 5A7” Ag - .571 V0? 8/! 77/ Ace. - ACID cop/00? BATH Agd‘ -.5‘// Vffl JTfi/P 6.00 - COPPER RECOVER Y 496/ - WA Vi)? 0210/9/05 M - N/C/rfl 5177/ $00 -.5‘/£V£/? fimeffi)’ BBL/VI - Blfififl N/C/(El. 8477/ 611% “ 8146K N/C‘KIZ 6,4777’ Au ‘ 6040 8477/ &N/ - 83/6/97 N/C/(EL 5A7’H 600-6010 RECOVERY /V/6‘ ‘ N/CWEL J'7'fl/P AuJ' “GOLD STRIP MhC/ -A//C/(£Z x4670 D/P Cr 'Cfl/POM/UM 5477/ GER-6010 85M RACKS PP - PM or»; AA/r-AA P/D .r/z VIA? IMF-€010 Fill/14010475 570/9465 05 - CHROM/l/M .rrA/P w/ —HrvoCA/ aA/c ACID D/P so - ems/r7 om H, ~MERCUH r 0m 4w,- wz swan/c A670 am cw - CYA/V/DE mp 88 - EUR/V/J‘h’l/VS 54335 L 57'- J‘A/VD TUMBLE BARREL 08" DR Y/IVG‘ 84/9351. SJ" JCRATCH BRUJ‘I-l JACK 6'8 “66508 BIA/6W HIV-#07 WA 7'53 [5 - l /6'H7' 80X 06- 056.95/46‘5/1" SJ“ JOLDER/NG A1670 6709465 57,3 PZAT/NG' ROOM CG CON/V lid ELKHART IND JANUARY A940 JCALE é"/’ ORA MV- ”.5. 84 Acid copper plating was practically eliminated and Rochelle salt cyanide solutions substituted. Acid zinc plating was abandoned and a bright du Pont cyanide zinc process was substituted. Changes from 1940 to 1941 In June 1940 the automatic silver plating machine was installed which necissitated a rather complete rearrangement as shown by Figure No. 4. The more important of these changes are as follows: 1. 8. Installation of automatic silver plating machine resulting in savings already noted. Retiring of several old type silver solutions. Installation of pilot plant for silver not yet removed parall- eling the automatic. Further consolidation of gold plating operations and install- ation of drip basins to catch splash. Removal of unnecessary partitions which produced congestion. Installation of extensive blower and dust systems on bright dip, strips, and buff jacks where noted by dotted lines. (15) (54) Provision of better storage facilities. Change in doors to avoid congestion in flow of work in and out of plating room. Grouping of copper, nickel, zinc, and brass plating systems in three lines, resulting in increased production speed and de- creased material handling. PROJBCTEP FUTURE DEVELOPFENTS ‘Work is at present going forward to perfect plating room practice in a number of ways. 1. Printed procedures for each plating cycle specifying s57": J . Hi __,j I h “E553 T fr I TI TI uiuiE I C. _ flag! a, a. / L G- GENERA 70R J - a yr; JACK W—R/Ms‘i: DIN/f 6 - WORK sews/r 6- 8m TCHBOARO 4 ~ 1 OCKER 9- WORKRA CK ‘ — —’ *1“ ————————— ”5‘ 04 ,3 xfl c w x @ H/voa 8rCu / (~an 8 B G 6 “I ‘ Cm? IV ““— F 5 H” [LJ r———J BI A05 ”60/ Ni ‘ NI 7 C 8 __ M/ ,5 5’2 C’ / MV 5 5 w h f . 8 fl 6 C C W W ENG/2 6N ” Br/ , M8 5"!” _fl}_ -— a 9L— 9 I L—_J _. — —_ — — 5 HIV/9 my ”Y RM My 1‘4er yr my c c B C C 6' lbs—{9 - —-—~ ~ ——«~— AUTOMA 776 m mm PZAfé'R — — — — H}— A —' ’7 M/ Viv A34 A 5 JV w ,wv F 701 5 N13 W 1 ’ (N j /V/ 2 w c c w H.504 w M/O A96 49 7 w / 8.91. 1 m4 06/ w :53 fi!’ mum/m mus p ECUZ} a z z t _____ Ii __ _. ® {— l i W 5 . - , ' +——C1—-4 W W »@®@: 2% y w 22.-see. 1.151 53% W awn, - CY/I/V/Df 60905;? 547/7 CW 2. - cm N/DE [INC 8/! TH 50 - ems/1 7 0m 5: - :70 RAGE flcu— Raf/{Elli cap/059 3AM Br z. ~ BR/G/fl' Z/NC BA m Hg - MERCURY D/P m- RACK Won/:65 emu ~aR/6‘H7 COPPIA 54m A; - 67L Vffl BA TH £450,101 PHUR/CAC/D o/p H - H000 1‘ axon/[R AcCu via/0 cop/on? 3.4271 Ag: - .r/z mm sm/P m c VAN/o: DIP C‘ALKAL/Nf CLEANER xv, -/V/6‘/(££ 547/1 Au - 601.0 34 m as - BURNIJ‘HING 3.43351. 1‘71 ’4 561M - amen lV/C/(fl 54m 600 - 60L 0 RECOVIR Y 6‘7 - SAND 70MB; E a ARREL sum-amok Mara mm A"? sow srfl/P oa-oRr/NG 521/9251. FLA TING 900M w 5r/Vz «an/M7 mam 54m can sow BELL RACK: 6‘6 - smug BENCH C. G. CONN Ata.’ wan/o {/57 DR/fl? N16"— N/C/I’iL .rm/p 6r: ‘CHROM/ UM J‘TR/P HIV-H07 WA rm KH ,q 7- IND Cr - CHROM/ UM 8/! 7H Mllcz-A/IC‘KIL .400 am #67 #7090011. 09/6 ACID 06 -0£6R£A:[R £1- A MA RC H /Q4/ JCAAEZ/V' OPAWMMLST 85 all variables to be placed on cards in holders and lOCated conveniently near the Operators work place. Conplete study of metal deposited on each part to obtain more aécurate costs. FeveIOpment of technique for studying dragout losses. Constant search for better methods, better processes, better metal and a better product. (1) (2) (3) (5) (6) (7) (8) 86 AFSTRACTS Amberg, R. J. Filter Aids for Filtration Net. Ind. 556-12-38 Anderson, E. A. and Reinhard, C. E. Alkaline Cleaning and Copper Flistering Ho. hev. 175-3-40 Anderson, E. A. How Zinc Alloy Die Castings are Plated Commercially No. Pev. 437-6-38 Anderson, E. A., Reinhard, C. E., and Kittlegberger The Plating of Zinc Alloy Pie Castings and Folled Zinc Met. Cl. Fin. 721-9-37 Anonymous Zialite Fright Copper Solution Pro. Fin. 40-8—38 Anonymous Recovering Precious Letals Let. Ind. 184-5-36 Ashelrod, R. S. and Erukhimova, N. A. Electrolytic Cleaning in Alkaline Solutions Mo. Rev. 476-6-40 Peaver, H. L. Series of Articles on Barrel Finishing Pro. Fin. 1937 to 1941 Belke, W. E. BevelOpment of Filters for Plating Solutions Let. Ind. 27-1-39 (10) (11) (12) (15) (14) (15) (16) (17) (18) (19) Camel, L. C. Alkaline Cleaning Lo. Rev. 777-11-59 Cleveland, T. K. Alkalis for Natal Cleaning Met. Fin. 478-9-40 Cleveland, T. K. Solution for Fetal Cleaning F0. Rev. 432-6-40 Conley, C; C. Determination of Drag-Out Loss ho. Rev. 355-5-39 Cosgrove, J. H. The Electrodeposition of Nickel on Zinc Mo. Fev. 7-12-56 Delorme, E. C. Ventilation of Acid tipping and Electroplating Rooms No. Rev. 112-2-38 Dodd, S. R. Alkaline Cleaning Net. Fin. 331-6-40 Egeberg, E. G. and Promisel, N. E. Brightening Agent for Silver Yet. Fin. 331-6-40 Egeberg, E. C. and Promisel, N. E. Silver Plating of Hollow Ware Pro. Fin. 5-4-37 Egeberg, E. G. and Promisel, N. E. Frightness of Electrodeposits and its Measurement 87 88 Net. Ind. 166-4-37 (20) Flowers, 1. C. Throwing Power and Current Distribution in Plating Paths ho. Rev. 47-11-36 46-12-36 44-1-37 (21) Graham, A. K. and Read, H. J. ‘ A Study of the Rochelle Salt Copper Plating Path Net. Ind. 559-11-37 Series of Articles) (22) Graham, A. K. and Read, H. J. Anodic Pehavior in Cyanide Copper Plating Paths Tet. Cl. Fin. 734-11-38 (23) Greenspan, L. New 00pper Plating Process Net. Ind. 227-5-40 (24) Greenspan, L. Electrodeposition of Eright Copper Elec. Soc. Preprint 78-13 (25) Hall, N. Wetting Agent Action and Control Pro. Fin. 52-6-40 (26) Helbig, W. A. Activated Carbon in Electroplating Solutions Net. Ind. 555-12-38 (27) Hickman, K.,'Weyerts, W. and Goehler, O. E. E1°°tr°13sis of Silver Rearing Solutions for the Recovery of Silver let. Ind. 349-9-36 (28) Hirsch, 8., Snyder, H., Jackson, R. and Verrelle, N. Effect of Free Sodium Cyanide and of Sodium Carbonate on the Cathode Efficiency of a Silver Plating Solution. (29) (30) (31) (32) (33) (34) (35) (36) 89 Pro A. E. S. 70-37 HOgaboom, G. B. Practical Pointers on the Use of Solvents and Alkaline Solutions in Fetal Cleaning Abr. Cl. heth. 20-12-56 HOgaboom, G. B. Alkali Cleaner and Acids on Lead Yet. Cl. Fin. 740-11-38 Fogaboom, G. F. Plating Economy Demands Control of Frag-Out Losses from Plating Solutions No. Rev. 48-12-36 Hogaboom, G. P. Removal of Carbonates from Metal Cyanide Solutions Net. Ind. 64-2-37 Hull, R. O. The Removal of Carbonate from Cyanide Plating Solutions by Gypsum Pro. A. E. P. 164-37 Kaye, A. L. Colloidal and Surface Aspects of Metal Cleaning and Finishing Net. Cl. Fin. 9-1-36 Kushner, J. B. hodern Gold Plating Pro. Fin. 30-9-40 (Series of Articles) Kushner, J. F. Feasurement of Drag Out Pet. Ind. 520-7-39 (s7) (38) (40) (41) (42) (43) (44) (45) Mattacotti, V. Impurities in Plating Solutions Net. Ind. 259-6-39 Nesle, F. C. A Resume of Silver Plating Pro. A. E. P. 104-37 Neyer, W. R. Fright Dipping of Non-ferrous Netals Ret. Ind. 401-9-39 Neyer, W. R. Earrel Furnishing Pet. Ind. 101-3-36 Meyer, W. R. Filtration of Electroplating Solutions het. Ind. 117-3-39 Meyer, W. R. Vethods of Mixing Filter Aids let. Ind. 558-12-38 Heyer, W. R. Cleaning of ietals Abr. Cl. Feth. 9-8-36 Muscio, G. Bright and Matte Dipping Pro. A. E. P. 262-38 Nicol, A. E. Variables in Silver Plating Solution Eet. Ind. (Lond.) 275-3-40 90 (46) (47) (48) (49) (50) (51) (52) (53) (54) Oplinger, F. F. The Develonment of a Process for High Speed Copper Plating from Cyanide Solutions No. Fev. 161-3-39 Reese, T. W. Analyzing and Controlling Petal Cleaning Operations Lo. Rev. 85-2-37 Pinker, E. C. Surface Films in hetal Cleaning Net. Ind. 20-1-40 Savage, Prank K. Recovery of Gold and Silver from Plating Solutions Ket. Ind. 160-4-39 Savage, F. K. Finishing Pand Instruments Let. Ind. 132-3-40 Savage, F. K. Alkaline Cleaners and Wetting Agents No. Rev. 445-6-38 Savage, F. F. and Pfefferle, P. R. Automatic Silver Plating No. Rev. 101-2-41 Smith, C. W. Purification and Filtration of Plating Solutions No. Rev. 687-10-39 Smith R. Fume Exhaust Design 131.0. A. E. P. 241-38 92 (55) Soderberg, G. Drag Out No. Rev. 156-3-37 (56) Strachan, E. K. Plater's Cleaning Compounds Pro. Fin. 21-8-38 (57) Towner, O. T. Finishing of Die Cast Products ho. Rev. 671-10-39 (58) wallace, E. v. D. Vapor Phase Fegreasing Pro. Fin. 16—3-37 (59) 'Weiner, R. Experiments on the Electroplating of Fright Silver Mo. Rev. 487-6-40 (60) Weisberg, L. Recent History of Certain Cobalt-Nickel Alloy Plating Solutions Elec. Soc. Preorint 77-18 (61) Weisberg, L. Cobalt-Nickel Plating Solutions Net. Fin. 518-6-40 (62) Weisberg, L. Cormorcial Feposition of Cobalt-Nickel Alloys Pet. Ind. 236-5-38 (63) Weisberg, L. Purifying Nickel Plating Solutions by Electrolysis Yet. Ind. 451-9-57 (64) West, A. C. Electric Cleaners Mn Us." 9429-11-11fl (65) (66) (67) (68) (69) (70) (71) Wood, C. 93 Commercial and Practical Aspects of Throwing Power as a Factor in the Character of Deposits. Mo. Rev. 11-7-36 Wood, R. Something New in Silver Plating hat. Ind. 166-4-38 Young, C. P. F. Fetal Cleaning Abr. Cl. Math. 7-1-37 Young, C. R. F. Metal Cleaning, Principles and Practice let. Ind. 446-9-57 Young, C. E. F. Solvent Degreasing Pro. Fin. 62410-37 Young, C. B. F. Study of Cyanide Cooper Plating Paths Net. Tnd. 560-12-38 Young, C. B. F. Nickel-Cobalt Alloy from Acid Sulphate Solutions Ret. Ind. 179-6-36 Abbreviations fibr. Cl. Path. - Abrasive & Cleaning Fethods Elec. Soc. - Electrochemical Society Bulletin Pet. Cl. Fin. - Fetal Cleaning & Finishing Net. Ind. - letal Industry New York Net. Ind. (Lond.) - Fetal Industry London No. Rev. - Monthly Feview American Electroplater's .Society Pro. A. E. S. - Annual Proceedings of Imerican Electroplater's Society Pro. Fin. - Products Finishing Page number, month number, and year number are given in order. O. \ \I o a V ‘ \\ 1 ‘l x J ‘1 D. ‘ 3 7‘ 'l . . n .. ,4 .1. . b u 6 o . . .. . .. ..b . a. .. . . .wl‘n “. p.3fi. . .... ... - .. 5.1... ..1 ., . ... 1......fivmfl73 id... ...- . . z. _ .. .. .. _. .7 4.... . w! ..?.am._.ufi.._, Rf .. .. . .343W2rauwrfi. « .. _. .... .. 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