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MONTHLY REVIEW

Published by the
American Electroplaters Society
Publication and Editorial Office
3040 Diversy Ave., Chicago

VOL. XVII    SEPTEMBER, 1930    No. 9


EDITORIAL

Now that the vacation season is over, and the various branches are again taking up the activities which have been dispensed with during July and August, it might not be out of order to remind our readers that the Electro-Platers Society expects this year to be an unusual one.

First of all there should be a great revival of interest in the Branches. There are hundreds of foreman platers who are not being reached by our Society. These men are in sympathy with us but are not a part of us. Every member beginning now should try to encourage all platers who are eligible for membership in the A.E.S. to become affiliated with our organization. Personal invitation to non-member, boosting the work of the Research Committee, or passing on your Monthly Review after it has been read are all means of bringing new recruits into our ranks, and are influences which help the plater who needs our help.

The Research Committee with Mr. Jacob Hay as Chairman should have the enthusiastic support, both moral and financial, of every plater and his employer. The work at the Bureau of Standards under Dr. Blum’s able leadership must be carried on. Our hearty co-operation and enthusiasm will go a long way towards making the tasks of the newly appointed Research Committee successful.

The Bureau of Education is to become a very vital factor in our branches this year. Mr. Albert Hirsch of Philadelphia Branch has recently been appointed chairman by President Gehling and is well qualified to bring the Bureau out of oblivion and make it ”go to work.” Every Branch should feel the influence of the Bureau of Education’ as each society will have a representative who will be able to keep in touch with the Chairman of the Bureau and by this method it is hoped more interesting and educational sessions will be held than we have had heretofore.

Platers Classes—Well, a whole page is at your disposal, branch secretaries, so when you have anything to report concerning the classes, just see if you can crowd the page. And in this connection, note all items of interest in your branch and send them in.

Associate Editors—There is always room in this Review for papers valuable to our membership. Will you not forward any such matter that may come into your possession, so that we can keep up to date and make this publication both interesting and instructive?

Next month we hope to hear from the Boston, Dayton, Grand Rapids, Cincinnati, Indianapolis, and Worcester Branches. Let’s make the October REVIEW 100% by having a report from every Secretary.


THE DEPOSITION OF NICKEL AT A LOW pH

BY H. C. Mougey and W. M. Phillips
Read by Mr. Phillips, Washington Convention, 1930

Our interest in pH in nickel solutions dates from the Letter Circular No. 82, issued by the Bureau of Standards, October 10, 1922, and the paper on this same subject in the Transactions of the American Electro-chemical Society, Vol. 41, 1922, page 333, by W. R. Thompson, ”Acidity of Nickel Depositing Solutions.” In this bulletin it was recommended that the pH be kept at about 5.7 and the statement was made that practically all satisfactory nickel plating is conducted in solutions with a pH between 5.4 and 6.3. Our plants as well as the electro-plating industry in general, followed these recommendations and for several years a pH of 5.7 was considered to be both satisfactory and necessary. Very careful measurements had to be made because a variation of even 0.1 pH came to be considered as very serious.

However, one of our production plants found that additions of sulphuric acid gave them better results, and, due to inaccuracies in determining pH, it was thought that the bath was being maintained at about 5.2. This value was just below that at which the indicator (brom cresol purple) would operate, and since excellent results were obtained, the matter was not investigated further. The improved quality of the work attracted attention to this plant, and at the same time laboratory work which had been started in our laboratory from theoretical considerations, indicated the desirability of low pH. In the course of a routine checking of the analyses of the nickel plating baths being used throughout our Corporation, it was found that the bath at this plant where the superior results were being obtained had gradually been lowered until it was 2.5.

This discovery caused consternation, and threw grave doubts on the ability of our laboratory to determine pH values, which only goes to show how firmly high pH was intrenched in everyone’s mind. However, immediate and careful checks in several laboratories using the quinhydrone electrode as well as colorimetric methods showed that the low pH values were correct. The low pH of the solution from the plant obtaining the good results was the only marked difference in the analyses of the solutions from the different units of the Corporation. This production experience which checked our laboratory findings, stimulated activity on this subject.

At this point we wish to emphasize that we are interested in low pH solutions, not because they are low, but because we are interested in better plating. The advent of rustless iron and stainless steel makes it necessary for the plating industry to greatly improve the quality of its work if it expects to survive. One of the best ways to improve is to put on a heavier plate, but with the high pH solutions this is difficult or impossible except at a great sacrifice of time, since the high pH solutions require low current densities. By the use of low pH solutions the current density can be greatly increased and the thicker plates that are required for durability may be deposited.

In this paper, we will endeavor to present the advantages and disadvantages of low pH solutions for nickel plating. Briefly, they are as follows:

ADVANTAGES

  1. Increase in plating range.
    It is possible to use a higher current density without peeling or cracking at the edges.
    The decreased time due to the use of the higher current density permits a better use of the equipment.
  2. Better anode corrosion. (Shows used anodes.) That is all that is left of an anode in a low pH bath. (Showing dagger-like anode.) You will notice you can bend that pretty easily, and break it, of course. At this particular plant, they are not satisfied with that kind of scrap, so they weld them all together and use them up entirely in that way. So they save everything but the squeal.
  3. No turbidity in the bath if the pH is kept sufficiently low (below about 3.0).
  4. The nickel is supplied to the solution from the anodes instead of by the addition of nickel salts, thus giving lower costs.

DISADVANTAGES

  1. There is a greater initial tendency for a low pH bath to cause pitting.
  2. Lower cathode efficiency.
  3. Too high anode corrosion under some conditions.
  4. Trouble will result if the pH is allowed to become high.
  5. There is a tendency for the pH to increase gradually, thus making it more difficult to control pH values.
  6. Since it is desirable to operate the low pH baths at high temperatures, the tanks and linings are restricted to materials which will permit such temperatures.
  7. For bright nickel plating the low pH bath gives best results at low temperatures while the high pH bath can be operated over a wider temperature range.
  8. The low pH bath is not suitable for plating zinc base die castings.
    It might be desirable to discuss these advantages and disadvantages in detail.

ADVANTAGES

  1. Increase in plating range.
    It is possible to use a higher current density without peeling or cracking at the edges. This means that pieces of irregular shape can be plated rapidly and satisfactorily. In addition, a thicker plate can be obtained within the permissible time limits. With either regular or irregular shaped pieces, more work with a definite thickness can be done in unit time, and less tanks, solutions, and floor space are required. The decreased floor space makes it possible to use shorter and thus cheaper conveyors, giving a saving in labor and an increase in production.
    Four sets of curves are given to illustrate this wider plating range possible with low pH. Curves ”a” and ”b” are based on a 5 minute plate on copper. These curves give data which may be used when a short plating time is used. For example, with a pH of 1.0 they show that even when the irregularity of the pieces is such that the current density between different areas varies as much as from 150 amps. per square foot to 10 amps. per square foot, a 5 minute plate at any temperature above 125° F. will give a good deposit. However, if the pH should be 5.0 and the temperature should be the same, that is, 125° minimum, the current density must not be over 28 amps. per square foot on the high spots or burning, peeling and cracking will occur. At a pH of 6.0 the maximum current density appears to be about 16 for the same temperature range.
    Curves ”C” and ”D” show the relations for current density and temperature for different pH solutions when it is desired to obtain a plate .0005” thick on a flat surface such as a test panel. It will be noted that when a pH of 6.0 is used it is almost impossible to obtain a deposit .0005” thick without having the plate burned, cracked or peeling.
    There is a marked difference between results obtained at pH 6.0 and those at pH 5.0 when heavy deposits are required, but the greatest gain is made at a pH of 2.0 or lower.
  2. Better anode corrosion.
    The low pH solutions give much better anode corrosion. It may be possible to change the solutions in other ways to secure similar results, but the fact remains that with low pH solutions of the conventional type the problem of corrosion of the anodes practically disappears.
  3. No turbidity in the bath if the pH is kept sufficiently low. This critical value is about 3.0. All platers are familiar with the turbidity in ordinary nickel plating baths with the resultant sludge. With low pH bath, this is entirely eliminated except perhaps in the case of high carbon anodes. It is not claimed that low pH solutions will dissolve free carbon.
  4. The nickel is supplied to the solution from the anodes instead of by the addition of nickel salts, thus giving lower costs since nickel in the form of anodes is much cheaper than nickel in the form of salts. Records in production show that one of our plants has been operating with a low pH bath of 9000 gallons for at least eighteen months without having to add any nickel salts. The loss due to drag-out is taken care of by nickel from the anodes, together with additions of free sulphuric acid.

DISADVANTAGES

  1. There is a greater initial tendency for a low pH bath to cause pitting. This may be due to an increase in the rate of solubility of the impurities in the anodes, sludge, cracks and corners of the tanks, tank linings, anode supports, etc. After the bath once gets adjusted we do not believe that there is any relation between pH and tendency to pit. Our records show that one of our production plants which has the most trouble from pitting is still operating on the old basis of high pH, and the plant which has been using low pH for about 18 months is relatively free from pitting troubles.
  2. Lower cathode efficiency.
    In general the high pH baths give cathode efficiencies of about 93 to 95% and the low pH baths give lower efficiencies, reaching as low as about 7070 for a pH of 1.0. This loss in cathode efficiency does affect current cost and generator cost but we do not consider this as a serious objection, and we feel that the savings due to low pH many times offset this small loss.
  3. Too high anode corrosion under some conditions. Most platers worry about getting the anodes to corrode fast enough. It is apparent that with the rapid corrosion of anodes with low pH baths there might be a tendency to accumulate too much nickel in solution. The drag-out tends to correct this excess and other means such as regulating the anode area will control it.
  4. Trouble will result if the pH is allowed to become high. Adoption of the low pH will enable the plater to get out more work and better work. If through inattention he allows the pH to rise he will find himself in trouble and plenty of it. He will be trying to obtain the advantages of a low pH bath with an old fashioned high pH bath, and this is difficult if not impossible.
  5. There is a tendency for the pH to increase gradually, thus making it more difficult to control pH values. This is more of an imaginary trouble than a real one for the low pH baths do not have to be controlled so closely. Instead of worrying about tenths of a pH the plater considers units. Where formerly a change of from 5.7 to 5.9 was considered as serious, the limits for a low pH bath would be somewhere between 1.0 and 2.5 or thereabouts. The excellent work of the Bureau of Standards on accurate determinations of pH values is more or less wasted on the nickel plater using low pH baths.
  6. Since it is desirable to operate the low pH baths at high temperatures the tanks and linings are limited to materials that will permit such temperatures. However, high pH baths should also be operated at high temperatures and so this objection loses most of its weight.
  7. For bright nickel plating the low pH bath gives best results at low temperatures, while the high pH bath can be operated over a wide temperature range. This is shown by the charts A and B. 8. The low pH bath is not suitable for plating zinc base die castings. This is a valid objection to the low pH bath, but at the same time we would appreciate it very much if someone would show us a bath that is entirely satisfactory for nickel plating zinc base die castings.
    We have tried to present in a brief manner the advantages and disadvantages of low pH nickel baths, but we recognize that much work remains to be done. We believe that with the co-operation of the American Electro-platers’ Society great strides can be made in the near future in improving nickel plating.

(See charts on following pages.)

MR. R. W. MITCHELL: I would like to ask a question—what effect the low pH has on the physical properties of the deposit?

MR. PHILLIPS: Well now, in order to answer that, I would like to have these panels themselves. We brought the evidence right here with us. We have the actual panels.
(Exhibits cards of panels from which data for the preceding curves had been drawn.)

MR. MITCHELL: With that high degree of acidity, do you have to take any precautions of mechanical agitation and so on to get hydrogen bubbles off of your cathodes?

MR. PHILLIPS: No, sir. This work has been done in a practically still bath.
Now these cards with the actual panels on them are the basis of those charts that you have, and they are physical proof of those charts. That is, you can see that the deposits are good where we say they are good by looking at those. You will see up there at 6.0 that the range is very narrow, and I may say that the bottom half of each of these panels is chromium plated. Now the reason for chromium plating that is that it is a pretty good test for the plating itself. If it won’t stand chromium plating in these days, we are not much interested in it. So we chrome plated the bottom half.

You will notice right along there that this narrows out, there is a very narrow range in 6, better in 5, better in 4, better in 3, better in 2, and look at the range here in 1. We got good plates all the way through there, almost, down to here (indicating panels). You will notice that cut-off there is just like the cut-off on your curve.

Now I just want to call something to your attention. You may say a panel is theoretical. A panel isn’t so theoretical, either; a panel is pretty hard to plate. That is, you are going to get quite a variation of distribution of current on a panel. Lots of things you plate in the plant are easier to plate than panels.

A paper by Schneiderman some time ago gave distribution of current for chromium plating, and it applies almost equally as well for this. This sketch indicates the current density at the different sections of a panel, as ascertained by actual measurement. So that you see that these panels are not favoring the thing very much.

DR. BLUM: Were the panels plated in large or small tanks?

MR. PHILLIPS: In small tanks.

DR. BLUM: Have you any data, Mr. Phillips, on the protective value of these coatings, porosity and so on?

MR. PHILLIPS: I would say that we have. We have a Florida rack at Miami, Florida, where we send all kinds of plated and painted and enameled goods for test. That is a pretty severe test. Well, in an effort to find out what plates were best, we sent plates from all divisions, including a lot of these low pH panels down there on a couple of occasions. On both occasions, these panels came back perfect. At the same time, we tested similar panels in both salt spray and calcium chloride. The salt spray test, as I remember it, went over 230 hours on panels that were plated through this production tank, and showed no tendency to porosity. They also stood up very, very well in the Florida climate which is pretty hard on everything.

MR. GEORGE HOGABOOM: Will you explain the calcium chloride test?

MR. PHILLIPS: Well, now, the reason for using calcium chloride is merely this, that calcium chloride is used in the winter in some States and cities to melt ice and snow. It is pretty hard on the plating, pretty hard on the paint and enamel, and we therefore thought it would be a good idea to test some of this work with calcium chloride, so we set up an intermittent calcium chloride spray; that is, it was sprayed for a certain time, then left stand for a certain time and sprayed again. But here is the sad part of it. Neither the salt spray nor the calcium chloride in any way checked our Florida results, except that we got this extremely long test in the salt spray, over 230 hours, on the panels that stood up so well in Florida: but the ones where the decision was closer, we didn’t get any coordination with either calcium chloride or the salt spray with the weather test.

DR. BLUM: Is the use of calcium chloride for dust settling objectionable?

MR. PHILLIPS: We do not so consider it. When it is used for settling dust, the material sinks into the road bed. When used for melting ice, it stays on top and forms a solution that readily splashes.

MR. GEORGE HOGABOOM: Can you make the calcium chloride test with the same apparatus used for the sodium chloride test?

MR. PHILLIPS: Yes.

MR. R. W. MITCHEL: Suppose, in the highly acid bath, you wanted one plate to be very hard for abrasion resistance, and another plate to be quite soft and ductile. Could you control the physical characteristics of the plate in any way to get the desired results?

MR. PHILLIPS: I would say the temperature of the solution would give you a degree of control.

MR. HARVEY GAUSING: What was the metal concentration of this solution carried at a low pH?

MR. PHILLIPS: On the chlorides, we are not definitely set; it is something we have to determine. We have got these baths operating both with low chlorides and relatively high, both successful, and we don’t know exactly on the chlorides; but there does seem to be an advantage in running the single salt content up perhaps as high as forty ounces.

MR. GAUSING: That is single sulphate?

MR. PHILLIPS: Yes.

MR. J. H. HOEFER: IS there any other method than the quinhydrone electrode for determining these low pH’s?

MR. PHILLIPS: Yes, you can get colorimetric sets that go down that low.

MR. HOGABOOM: I am wondering if the question of pitting isn’t associated with the deposition of the metallic impurities that may be in the bath in the original state. Remember the work that was done by Fink and Rohman and presented at the last meeting of the Electrochemical Society at St. Louis? When they wanted to get a perfectly pure nickel deposit, they used a pH of about 2. And in the discussion, Dr. Fink admitted that they had excessive pitting when they were depositing out the copper. Now in copper refining, when the nickel comes to a certain concentration, it will be deposited. When you have these metallic impurities like iron and copper in this bath, when they come to a certain concentration, is there a possibility there would be either a cementation or electrodeposition and that would cause pitting and when the concentration has been decreased, why your pitting stops. And also that when you add such a thing as hydrogen peroxide, you change the cathode polarization, and therefore stop the deposition of those metals until that hydrogen peroxide has lost its value, and then they begin to pit out again? And isn’t that one of the reasons why there seems to be a necessity as the bath grows older to increase the amount of hydrogen peroxide that must be added to keep that bath from pitting?

MR. H. C. MOUGEY: With our low pH baths we do not increase the hydrogen peroxide,—it gets less and less.

MR. HOGABOOM: That would bear it out, because as you get out your impurities, then the metallic impurities in there wouldn’t have such an effect on pitting, and therefore the addition of hydrogen peroxide would be eliminated, because hydrogen peroxide would only be added to change the polarization of the cathode so as to prevent those impurities. Now if those impurities are plated out in the beginning, then the necessity of using hydrogen peroxide would be greatly increased, and that bears out your experience.

MR. PHILLIPS: It does exactly. Now I may say we used, when we started this low pH bath, 300 gallons of peroxide in a 9,000 gallon bath in two weeks. That has gotten down to a point where 300 gallons would last us for at least three months, if not very much longer. We use very little peroxide at the present time.

MR. HOGABOOM: I would like to ask Mr. Maugey another question. If there is iron in the solution, suppose you use sodium perborate. Is that better than hydrogen peroxide, or as good?

MR. MAUGEY: Mr. Phillips can answer that.

MR. PHILLIPS: The use of sodium perborate was effective in preventing pitting, but we do not believe that the continued use of sodium perborate would be so very good in a low pH bath, or perhaps any other bath, on account of the increasing amount of sodium in the bath. We would rather perhaps get a little less effect with hydrogen peroxide than continue to use sodium perborate in the bath.

DR. BLUM: It might be well, Mr. Phillips, to emphasize a point you already brought out that a bath of this kind is self sustaining in the sense that the term has been used by some platers; in other words, that you are getting your metal from your anodes. That means, then, all the more, the importance of using pure nickel anodes, even though, as you say, this solution will corrode anything except carbon. That very fact means that you want to have pure nickel anodes; otherwise you will be dissolving all your copper, iron, and everything else that is in them, so that it would look to me as if the purest nickel anode you can get would be especially desirable for this type of solution, because you do not have to add any nickel salts, and therefore if you can control the anodes you can certainly get pure sulphuric acid and consequently you are not adding additional impurities to the solution from time to time.

MR. PHILLIPS: That is certainly quite true. You don’t want to take advantage of this bath to buy cheap nickel anodes just because they will corrode. If you do, you will probably ruin your nickel solution after a while. Take advantage of it, rather, to dissolve the purest and best anodes you can get because you can dissolve them. You can dissolve even cathode nickel in good order.

MR. PEARSON: What current density do you use for work in general with this solution?

MR. PHILLIPS: About 35 or 40 amperes per square foot has been our general practice.

MR. PEARSON: And about how long does it take a new solution before it works satisfactorily?

MR. PHILLIPS: That is an awfully tough question, that last one. We have only been through that a few times. It took us about two months to get what we really considered a satisfactory product out of one of these baths. But we believe we can do it in a shorter period next time.

MR. HOGABOOM: Have you tried purifying your bath previous to using it?

MR. PHILLIPS: No, we haven’t. We took the bath pretty much as it was, and then made it worse, for this reason. We had a coil made of a certain trade name bronze which I won’t mention, but that coil dissolved in our bath, and that didn’t particularly help things.

MR. WM. GRUND: In putting chromium deposits over this range, that is, 1 and 2 pH on this nickel, does the current density have to be reduced to keep that coating from lifting off?

MR. PHILLIPS: NO, YOU can increase it very materially. I would say that is one of the big advantages, that your deposit will be a better deposit for withstanding such chromium deposits. I don’t believe we would have done it if it hadn’t been for chromium.

MR. JAMESON: You spoke of not using sodium perborate on account of the sodium building up in the solution. Just what is your objection to sodium, and furthermore, do you or do you not use sodium chloride in the first place as a means of introducing chloride in your bath?

MR. PHILLIPS: I will answer your last question first. We don’t use sodium chloride to introduce chloride. We use nickel chloride. And the reason we don’t want to put sodium in the bath is we don’t know what sodium will do. We know we can work without it; we don’t know whether we can work with it or not, so we are not going to put it in.

MR. G. B. HOGABOOM: Isn’t it true that a bath containing sodium chloride has a greater tendency to run to alkalinity than one which contains nickel chloride, and may there not be some effect at the cathode where you get more alkaline film?

MR. MAUGEY: That is one of the theoretical reasons that made us start to work on the elimination of sodium, and we found with certain baths we would get pitting when we added sodium, and we could eliminate the pitting by leaving out the sodium. But we aren’t positive now that sodium is as bad as we once thought it was, but we know that we can get along without it, and prefer to be without it.

MR. HOGABOOM: Would the pitting be accompanied with precipitation of nickel hydrate rather than gas pitting?

MR. MAUGEY: No, it doesn’t seem to; it just seems to cause pitting on the work.

MR. PHILLIPS: Mr. Maugey, there seemed to be a relation between the presence of ferrous iron and sodium in those first experiments. That is, where we had both ferrous iron and sodium, we got a great many more pits than if we had either one by itself.

MR. HARVEY GAUSING: Do you experience any more pitting in this low pH solution after a shut-down of a day or two?—The solution getting cold, and then warming it up again, say over Saturday and Sunday? Do you experience pitting then more than from one day to the next

MR. PHILLIPS: Not as much. That is an experience we have constantly with the high pH baths, but we don’t have that same experience with the low pH baths. Our shut-downs don’t seem to bother us very much.

MR. JAMESON: It seems rather strange to hear of pitting in a nickel solution. I have used common ordinary salt for the last three years in a 6,000 gallon bath, and pitting is certainly unknown in our plant. Now this idea of adding nickel chloride because you don’t want the sodium element in there,—if you consider it a fact that you are buying nickel chloride, I think it is about 40¢ a pound, and only 20% available chlorine present in it, whereas you can buy common salt at 3¢ a pound, and about 50% of which is available chlorine. I can’t just reconcile the fact that sodium is responsible for the pitting, because, as I said, we never have any. When I say ”never,” I may be exaggerating, but we don’t have any pitting to speak of; have not had for the past three years.

Now we do add a certain amount of sodium perborate in our nickel tanks every night, and we also add a certain amount of hydrochloric acid to our tanks every night to be sure we don’t experience any pitting the next day. I would like to hear something said about that.

MR. PHILLIPS: Mr. Jameson, the whole thing is this. Perhaps we were more cautious than we had to be. But when we have a 9,000 gallon bath and the total production of the plant to contend with, we would rather spend a little money just to be extra careful. We don’t know that sodium chloride would put us in trouble, but we know that we are playing it safe when we don’t put any sodium radical in, and that is the reason for doing it. The other thing may be perfectly all right.

MR. B. G. DAW: Do you find the deposit more uniform on irregular parts than with the higher pH solution?—Better throwing power, in other words?

MR. PHILLIPS: Those panels demonstrate that very nicely; that is when you realize for instance that this 1.0 pH panel, and by the way we haven’t called your attention to the fact that these second cards we put up here, we plated half a thousandth on those, instead of plating for five minutes as we did in the other series. But you are going to have a very much wider range. Now your irregular object burns and peels on the edges simply because you have a current concentration on those edges. Well, if you can plate from we will say 50 amperes to 150) you will be pretty sure then that those edges won’t burn. If you can only plate from we will say 10 to 20, you can be pretty sure they will burn.

MR. FERRIS: Those samples that were sent to Florida for test,— were they plated directly on steel, or nickel, copper and nickel?

MR. PHILLIPS: We tried all kinds. Not all programs, but all the programs in use in the different divisions of General Motors. Some were nickel copper and nickel, some copper and nickel, and so on, the different kinds.
Possibly a rather interesting thing, without taking too much time, is that we had two panels, two sets of panels that came through very well. They both had about one thousandth of an inch deposit, about a thousandth and a quarter of deposit. In one case the panel was 50% copper and 50% nickel, and about twenty-five millionths of an inch of chromium, and the other one was only about 10% copper, and almost a thousandth of nickel, and the same amount of chromium, and they were both good panels, but there was about a thousandth of deposit on both of them, which makes this old thousandth look pretty good.

MR. R. F. CLARK: May I ask if you advise a low pH in a plating barrel which has a horizontal cylinder?

MR. PHILLIPS: I regret to say we have done no work on the plating barrel with low pH baths.

Question: Have you made any measurements on the actual cathode efficiency? That is, you said the cathode efficiency is low. I was wondering what that would be.

MR. MAUGEY: We made many measurements on cathode efficiency and the cathode efficiency does drop as the pH drops, but the cathode efficiency even on the pH of 1.0 is about 70%, so we don’t believe the cathode efficiency is a real factor in our work.

DR. BLUM: That question of cathode efficiency is tied up with a previous question which you didn’t quite answer on throwing power, distribution of deposit as distinguished from the question of whether the deposits were good or not. If the cathode efficiency is low, but uniformly low, you will still get good throwing power. If, however, it is low and drops off more rapidly at that low current density than a high pH solution does, you will get poor throwing power. How do you know which is the case?

MR. PHILLIPS: We have never made any throwing power measurements. We only know we can plate the pieces we have to plate, that is all.

MR. MAUGEY: We have to plate them with chromium, and chromium is very difficult to throw. Therefore when working with nickel it throws very much better than chromium, so we never got interested in the possible differences in throwing power because we have to plate them all with chromium anyway.

Question: On these curves here, there is no mention made of the amount of nickel sulphate carried in the solution. Now certainly there is going to be a difference if you run one of these curves with 16 ounces of nickel sulphate and another one at 32 ounces of nickel sulphate.

MR. MAUGEY: Those are all the same in nickel sulphate. They are the Watts bath, the standard Watts bath, 32 ounces of nickel sulphate.

MR. PHILLIPS: And I may say at 40 ounces in a production plant that the results at least are very comparable.

MR. G. A. WILSON: I want to ask if you maintain running the bath sixteen or eighteen months?

MR. PHILLIPS: Yes.

MR. WILSON: Without the addition of any chemicals?

MR. PHILLIPS: I wouldn’t say no chemicals, but no nickel.

MR. GAUSING: Would you use commercial sulphuric acid to maintain the acidity of this solution?

MR. PHILLIPS: You could use commercial sulphuric acid. Frankly, we don’t. We buy pure sulphuric acid for the job. We are just over-cautious, perhaps. Maybe in a year or two we will broaden out a little bit.

MR. GAUSING: You have never used any hydrofluoric acid?

MR. PHILLIPS: No, sir, we couldn’t. We have in some cases lead lined tanks and couldn’t use that.

MR. JAMESON: How about hydrochloric acid?

MR. PHILLIPS: Well, hydrochloric acid, of course, might be used. We haven’t done any work on it.

MR. WM. SNYDER: Has any thought been given to any other acid than those mentioned here for additions?—such as phenol or some other acid?

MR. PHILLIPS: Well, getting back to Mr. Pitschner’s paper on this buffing, we had thought of using an acid such as perhaps acetic acid as a buffer for these lower pH baths so as to prevent shifting around too much. We haven’t, for the purpose of reducing pH, particularly, thought of any other acid.

MR. MAUGEY: Yes, I might say that was one of the things that prompted this work in the beginning. We used a nickel acetate bath, and acetic acid, and got these wonderful results with low pH. And that was one of the things we wanted to find out, why we got those good results, and we found we got those good results with any bath as long as we had the pH low.

Question: We didn’t hear what the lining of your tank was. Is it tar or asphalt?

MR. PHILLIPS: Rubber. The biggest operation we have is in a rubber lined steel tank.

Question: And your heating element, what is that made of?

MR. PHILLIPS: The heating elements are of lead pipe.

MR. WM. GRUND: Speaking of chloride, is there any way of dissolving enough nickel chloride in a nickel solution, we will say where the pH changes at the rate of from 5.8 to 6.4, in a matter of three or four hours,—is there any way of dissolving enough nickel chloride or putting it in solution to get quick action in the results? I might leave that for Mr. Hogaboom, to answer that question.

MR. HOGABOOM: I can’t see the necessity of using nickel chloride for correcting the pH.

MR. GRUND: I thought that was the way this man made the remark they used nickel chloride.

MR. PHILLIPS: The favorite use of the chloride has been to promote anode corrosion. I don’t think it is put in for any other purpose particularly; and our experience with this low pH is that we are at this time doubtful as to how much if any chloride we need. We just don’t know. It is possible we don’t need any.

Well, we have certainly had a lot of discussion.

CHAIRMAN VAN DERAU: I believe in another year this is going to be a very active subject. I think we owe Mr. Maugey and Mr. Phillips a rising vote of thanks for the way they brought this up at our Convention.

(Rising vote extended)


PRACTICAL LACQUER EVALUATION FROM THE PLATER’S STANDPOINT

BY R. V. Kirk
Read at Washington Convention, 1930

The object of this paper is to suggest to the plater who uses lacquer means by which he may, in a quick and empirical, yet practical way, test and evaluate the many lacquers offered for his use.

The plater with a well equipped chemical laboratory at his disposal will have less need for these suggestions than will his less fortunate brother, who is forced to depend on the usual plating shop equipment to test his lacquers. However, these tests, performed as they are simply with ordinary shop equipment, may not only serve to augment the regular physical-chemical laboratory tests, but may even replace them when the proper scientific equipment is lacking.

Naturally, many of these tests were suggested to us by lacquer consumers themselves; in many cases they represent specifications that had to be met, and since they came to our attention in this way, we feel that they may be of interest to other lacquer users, who may not be familiar with them.

Let us consider first clear lacquers as distinguished from pigmented lacquers,—lacquer enamels. What qualities will the electroplater hope to find in a clear lacquer? First, I should say, would come adhesion. If the lacquer is not going to stick, and stick hard and fast to the surface to which it is applied, there is very little point in applying it in the first place.

A very simple test, and a very significant test for this quality is this: Flow the lacquer in question down on a piece of metal, preferably beside a lacquer known to have satisfactory adhesion. Put the metal plate in the oven at about 150-175 degrees F. for about ten minutes; then when the metal is cool, simply cut the lacquer away from the metal with a sharp knife. Lacquers have not yet reached a point where they cannot be cut by a good knife; but a really adhesive lacquer will resist the cutting, and will come away from the metal only where the knife actually cuts it away. A lacquer without the proper adhesion will come away all along the line of the cut in a jagged, irregular line, the film in the immediate neighborhood of the cut being removed also. If the lacquer film coheres together to a greater degree than it adheres to the metal, it may be removed in a sheet from the line of the cut. This brass sheet will serve to illustrate this point. (Shows brass sheet.)

Immediately after this prime factor of adhesion, and closely coupled with it, is the question of flexibility. Metal lacquer users in general (no one more so than those in the electro-plating industries) are coming to realize that flexibility in a lacquer is a point which cannot be overlooked, even when the lacquered object is not subjected to bending. Flexibility is the quality which enables a lacquer to resist chipping and flaking; flexibility in a lacquer, coupled with adhesion, is the quality which enables your product to withstand hard usage. Of course, the use of really flexible lacquers often enables the manufacturer to save considerable time and labor by doing his lacquering in the sheet, and any blanking and forming required subsequent to the lacquering. A little later, in discussing lacquer enamels, I should like to bring out this point a little more fully. At this point I wish to bring to your attention a test for flexibility which was suggested to us by a manufacturer of clock dials. The dial is of brass, silver plated, and then lacquered in the sheet. The blanking and forming operations are then performed. Then as a test for flexibility the dial is placed in an acid copper bath, and this acid copper bath tells a very interesting tale. When the lacquer is really flexible, it is not at all injured; but where it is the least bit brittle, it has chipped away, and the copper has plated out on the dial. This test will detect lacquer failure even where it is not actually apparent to the eye.

With adhesion and flexibility considered, the next point to consider in a lacquer is body. This quality should not be confused with viscosity. It is quite possible for a lacquer with high viscosity to have very little body. The body of a lacquer depends upon the actual solid material in the lacquer. These are the ingredients, of course, which actually do the work of protecting the surface upon which the lacquer is applied. With an analytical balance at his disposal, one may actually determine the body of a lacquer, and express it numerically as percent solids. Without such equipment, however, it is possible to obtain a very good idea of the relative body of a lacquer in this way: First, as a control, use a lacquer which is known to have satisfactory body. Then, in comparing it with another lacquer, thin the two down to the same viscosity, then flow them down, side by side, on a piece of metal. When they are completely dry, the actual solid material present in each lacquer may be easily compared by observing the thickness of film left in each case. The lacquers in these two tubes (exhibiting tubes) while quite different in viscosity, have actually the same body. When the more viscous is thinned down to the consistency of the thinner one, and the two flowed out, the difference in body at the same viscosity is readily apparent. The only fair way of comparing the body of lacquers is at uniform viscosity. At this point I should like to mention that, while body is an important consideration in evaluating a lacquer, it should be borne in mind that high body is only desirable when the first two qualities I have mentioned—adhesion and flexibility—are also present. In other words, rather sacrifice a percent or two of solids than the slightest degree of adhesion or flexibility. Body is only a factor in rating two lacquers when the adhesion and flexibility are comparable and in special cases where extreme thickness of coat is required to protect the work.

These qualities I have mentioned are, in general, the most important in rating clear lacquers. There are, of course, several others,—lustre, flow and drying time—but these are qualities which may be easily observed with a few moments’ work with the lacquer, and there are no tests for these qualities more reliable than the spray man’s eyes and experience.

Before leaving the subject of clear lacquers, there are one or two tests for special purpose lacquers which may prove of interest. The rather mysterious phenomenon called ”spotting out” is a bugbear in the lacquered metal industries. A quick test to gauge the resistance a lacquer will offer to this type of failure is performed this way: A piece of lacquered brass or silver is simply heated over an open flame, heating gently so that only a slight, gradual discoloration of the surface is effected. If the lacquer has a tendency to cause the metal to ”spot out,” the spots will show up very quickly in this test. Any lacquer will discolor in this test, but the discoloration should be uniform, and free from spots.

In the field of silver lacquering, a very interesting test, suggested to us by a manufacturer of shoe buckles, is performed in this way:

The silver plated article is finished in the usual way, by spraying or dipping, and when it is dry, it is placed in an oven at 125 degrees F. with a rubber band-around it, for several hours, or over night. At the end of this time, if the lacquer has not properly protected the silver surface, the sulphur compounds in the rubber will have permeated the lacquer film and discolored the silver. This is a very practical test, since it is contamination from sulphur compounds in the air and the human skin or in packing materials which causes silver articles to tarnish and turn black, and in this test the extent to which a lacquer will retard this action may be gauged. This test may be run also with silver in the flat sheet, substituting a flat piece of rubber for the rubber band. I have here (exhibiting specimen) a piece of silver plated brass, which has been lacquered on one half with one type of silver lacquer, and on the other half with a second and unsatisfactory silver lacquer. A piece of rubber was placed on the metal, just over the intersection of the two lacquers, so that it partially covered each of them. A piece of tissue paper was placed between the two, to prevent their sticking together, and they were placed in the oven at 125 degrees F. over night, in the morning the extent of discoloration being observed. It will be noted that while one half of the sheet retains practically the same color it had before the test, the other is badly discolored where the rubber was over it.

I should like to call your attention to the number of tests in which an oven is used. A good oven is an extremely useful asset in the testing of lacquers, especially in testing for permanent flexibility. In an oven the brittling effect of months of ageing can be obtained in a few hours.

Passing now to the consideration of lacquer enamels, the tests which have been outlined for clear lacquers are, in many cases, equally adaptable for testing lacquer enamels. Adhesion and flexibility are prime factors in good enamels, just as they are in clear lacquers. The extreme flexibility demands which some users of lacquer enamels make on their finishing materials, make imperative the use of a quick test for this characteristic. For instance the manufacturer of these metal racks (exhibiting rack) for the display of spools of thread, first applies the black enamel by means of a coating machine, and does all his blanking, forming and crimping after the lacquer is dry. It is obvious that no ordinary lacquer enamel would suit his purpose; he could use a quick test for flexibility in lacquer enamels. Another process in which extreme flexibility is required is in the finishing of metal strip. The steel strip is first lacquered, and then the very severe blanking and punching operations are performed. Here again, a quick test for flexibility would quickly eliminate from consideration the many lacquer enamels which would fail in this process. A certain manufacturer of aluminum foil does his lacquering enamelling first, and then the embossing needed for label work is done. Here is another case where the flexibility demands are extreme. In all these cases, the desirability for a simple flexibility test is evident; one that will not require that the machines be set up or large quantities of lacquer obtained for an actual plant test. Just such a simple test has been devised. It consists merely of flowing down the lacquer enamel on a piece of metal, baking, and when cool, cutting through the film with a pair of shears. If the lacquer flakes away from the cut, or if it peels away, any of the manufacturers I mentioned above will know that there is far less chance of the lacquer standing up under their tests than if the lacquer adheres just as firmly at the cut edge as it does on any other part of the surface. This panel (exhibiting panel) will serve to illustrate this point. As far as the drawing operations are concerned, any die will reveal as much about a lacquer enamel in a few moments as any expensive ductility machine. A certain manufacturer of bathroom fixtures has his own test for flexibility. Parts of these fixtures are composed of wire, and this wire being the most flexible part of the fixture, he lacquers the wire and lets it stand around for three months. This is longer than most of us care to wait for our results, but the results when obtained are very gratifying and reassuring.

Body in the lacquer enamel field holds the same position it does in the field of clear lacquers. It is an important factor in the building of good lacquers, provided it rests on a firm foundation of adhesion and flexibility:

For the other general qualities a good lacquer enamel should have, lustre, flow, etc., we must simply depend on our eyes and experience.

There is one phase of this subject which I should like to touch on before closing, and that is the proper attitude which should exist between the users of lacquers and the manufacturers, in regard to tests and specifications. In former times, it was considered good policy for the lacquer manufacturer to keep the consumer as much in the dark as possible regarding lacquers, and on the other hand for the user not to reveal what tests it had to pass, or just what he expected from it in the way of service. This attitude militates very strongly against real progress and is now rapidly disappearing. If the lacquer manufacturer can know in advance just what is expected of his product, much time can be saved, and many headaches averted by both parties. A case of our own, serving to illustrate this point, occurred in the case of a manufacturer of collapsible tubes. One manufacturer had been getting his lacquer at rather high viscosity, and was applying a very heavy coat to his product. A second manufacturer, making the same type of product, had an entirely different idea of the correct way to finish tubes. He was trying to apply a very thin coat, practically printing the lacquer on his tubes, and the material with which the first manufacturer was obtaining good results was entirely unsuited to him. He needed a lacquer at a very thin viscosity, but we were not aware of this until several unsatisfactory tests had been made and considerable time lost. If we had known at once just how the lacquer was to be applied, much time would have been saved, and the desired results obtained much sooner.

I cannot make my plea for this closer, franker relationship between buyer and seller too strong. The lacquer manufacturer has, or should have, the technical knowledge necessary for the compound of good lacquers; the lacquer user is familiar with the failings common to lacquers, and the requirements which he must find in a lacquer; without a knowledge of both sides of the question, the production of really successful lacquers is impossible. Therefore, if we both approach the question on an even footing, if the lacquer manufacturer can know beforehand just what his product will be required to do, many of the problems which today perplex both the makers and the users of lacquers will be solved, with highly beneficial results to all parties concerned.

(Applause. )

DR. E. B. SANIGAR: Most of your tests, I take it, would be affected by the cleanliness of the brass upon which you make them?

MR. KIRK: Yes, certainly the brass has to be properly cleaned in all cases. I am taking that for granted.

DR. SANIGAR: That is really an essential point of the test.

MR. RAYMOND LOPEZ: Have you made any perspiration tests? For instance, take an article with a handle which is used a great deal; there is a tendency, if the lacquer is not satisfactory, for the perspiration to penetrate to the silver or brass, whatever it may be.

MR. KIRK: That is a very difficult situation to duplicate without some chemical equipment. That can be done with moist hydrogen sulphide, for instance, in a dessicator, but that requires laboratory equipment, and I was trying to confine myself entirely to tests that could be made in the shop. We have done that; that is a good test for silver and brass lacquers, but it requires chemical equipment.

MR. LOPEZ: Well, we do that with a dessicator, but I thought perhaps you might have a practical test where it could be done without instruments.

(Session adjourned.)


THE PROTECTIVE VALUE OF A COPPER STRIKE

BY W. S. Barrows
Read at Washington Convention, 1930

Twenty years ago, the question of the advisability of copper plating steel or iron previous to nickeling was a common one among platers. It was usually regarded as good practice on sheet steel, steel tubing, forgings, etc., but inadvisable on cast iron. If the process was eliminated, it was generally due to economic reasons rather than because it was considered useless from the standpoint of producing more durable protective coatings. Nor was the copper strike discontinued, but copper undercoatings generally received the taboo in many plants.

Within the past ten years, motor car trimmings of steel have been finished with only a nickel coating averaging in thickness between 0.0001 and 0.0002 inch.

Naturally such coatings were productive of much dissatisfaction to both the manufacturer and the buying public. Within the past five years, copper coatings of at least 0.0003 inch, followed by nickel at least 0.0003 inch thick, have been specified. Furthermore, the deposition of nickel directly upon the steel, followed by copper and a subsequent coating of nickel, has been favored by many, and regarded by some as the final word in combining nickel and copper deposits for protective purposes.

One writer has stated, ”If copper plated steel is to have only a thin protective coating, and does not require buffing, 10 to 15 minutes will suffice. If the surfaces are to be buffed after nickeling, then 30 to 60 minutes will be required to produce a sufficiently heavy nickel coating; 8 to 10 amps. per sq. foot at 3 or 4 volts.”

Thirty years ago, we employed the cyanide copper bath for the production of a mere flash of copper previous to nickeling steel surfaces, but the nickel coatings were seldom less than 0.002 in. thick, and the protection afforded to steel of that period was in general quite satisfactory. We polished good steel surfaces in those days; today we merely skim over the surface of exceedingly inferior steel with one wheel, and leave innumerable pits, cavities and inclusions which present an altogether different condition for treatment by the plater.

In an attempt to determine the best method of using copper and nickel on extremely soft, porous sheet steel of 25 gage, which was to be used in the manufacture of a product which would be subjected to a wide range of climatic conditions in various parts of the world, I began a series of tests which as yet unfinished have proven rather interesting, and give promise of some really helpful information. The tests were conducted in four series:

Series A—Total deposits produced in less than five minutes.

Series B—Total deposits not less than 5 min. or more than 10 minutes.

Series C—Total deposits not less than 10 min. or more than one hour.

Series D—Total deposits over one hour.

Fabricated parts were taken at random from stock in process. The surfaces of each sample were used in the tests. All samples were prepared in the same manner up to point of introduction to dip preliminary to plating.

In Series A, results were practically the same on samples nickeled direct for 1 minute and on those nickeled direct for 4 minutes at the same current density.

Ni-2 min. at 20 amps. per sq. ft. Bath temperature 90°
Cu-5 sec. at 150 amps. per sq. ft. Bath temperature 120°
Ni-2 min. at 20 amps. per sq. ft. Bath temperature 90°

Gave 50% better production than a 3 minute deposit of nickel direct on steel. Pits in all samples were enlarged, areas around pits were corroded.

In Series B, samples nickeled direct 5 min. at 10 amps. per sq. ft. bath temp. 90 were corroded over 95 per cent of surface. 10 min. nickel direct was corroded over fully 50 per cent of surface.

Samples which received Ni-2 min., Cu-1 min., Ni-2 min, C. D. for nickel being 20 amps. per sq. ft., and C. D. for copper being 150 amps. per sq. ft., corroded only at pits, edges of pits were sharp and clean, surrounding areas not affected.

Samples given: Cu-1 min., Ni-2 min., Cu-1 min., Ni-3 min., were in better condition after 193 hours salt spray test than samples given Cu flash (approximately 5 seconds), Ni-2 min., Cu-flash, Ni-3 min., were at expiration of 26 hours salt spray test.

In Series C, where the minimum deposit was 10 min. and maximum deposit was 60 min., we obtained contradictory results. Samples which received deposits of nickel direct for 60 min. were corroded over 60 per cent of areas and surfaces surrounding pits were seriously affected.

Samples with Ni-5 min., Cu-5 min., Ni-50 min., buffed, were unaffected except at pits, surface around pit was unaffected, edges sharp and clean.

Ni-3 min., Cu-3 min., Ni-15 min. was affected over only 10 per cent of surface, while Cu flash or approximately 5 seconds, Ni-60 min., was seriously attacked over fully 75 per cent of surfaces.

Not until we began Series D (deposits of over 60 min.) did we obtain anything which gave evidence of being sufficiently durable to meet even local climatic conditions satisfactorily. In this series the samples were treated by various methods to ascertain the value of such special manipulations.

Cu-3 min.
Ni-1-l/2 hrs.
Buffed

}

95% of surface unaffected Pits large, edges ragged.

Cu-5 min.
Buffed min
Ni-1-1/2 hrs.
Buffed

}

98% of surface unaffected. Pits were only portions attacked, edges sharp, clean.

Cu-10 min.
Wire brushed
Ni-70 min.

}

Equally as good condition as
No rust or other indication of attack at pits.

}

Ni-10 min.
Cu-10 min.
Wire brushed
Ni-60 min.


Cu-30 min.
Buffed
Ni-2-1/2 hrs.
—30 amps. sq. ft. Bath temperature 120° F.

— 5 amps. sq. ft. Bath temperature 70° F.

These samples were almost perfect. Two or three pits defied protection by the coatings. Copper was exposed around these pits, but steel was not exposed or attacked; otherwise surfaces were in splendid condition.

The next record does not indicate that the experimenter became affected by the heat or obsessed with the idea of ”repeat the operation,” but it does indicate to what extent we diversified our methods.

Cu-5 min.—30 amps. sq. ft. Bath temperature 120° F.
Wire brushed
Cu-5 min.
Wire brushed Cu-5 min.
Wire brushed
Ni-2-1/2 hrs.—5 amps. sq. f t. Bath temperature 70° F.
Buffed

These samples were the only ones accepted as sufficiently perfect. The pits were sealed, not a trace of corrosion was detected after 308 hours in salt spray and subsequent exposure of 6 months on roof of factory directly in front of fan outlet from plating department.

Therefore, at this point in our experiments we are hopeful of producing a protective coating of copper and nickel which will afford satisfactory protection to steel surfaces in any climate permanently endured by man, if we can invent a contraption which will alternate plating and brushing operations without aid of manual labor.

Copper strikes of the flash order did not prove beneficial. Copper strikes of one minute duration did prove of value.
Initial deposits of nickel, followed by a copper strike of 1, 2 or 3 minutes’ duration, did not give greater protection than initial coatings of copper followed by nickel deposits approximately one-third thicker than in the former instance.

On good clean steel surfaces, free from pits, cavities or inclusions, the samples given 1 min. and 2 min. copper strike at 150 amps. per sq. ft. in a bath at 120° F. were decidedly more resistant to salt spray and exposure tests than samples given 30 seconds copper strike or nickeled direct on steel.

The copper solution employed in these tests is one which was made by removing 75 gallons of an excessively dense cyanide copper solution and diluting the 75 gallons to make 150 gallons. At time of tests the free cyanide content was 1.1 oz. per gallon, and the metal content was 3.25 oz. per gallon.

Nickel deposits were obtained from one bath only at a C. D. of 20 amps. per sq. ft. with bath temperature of 90, except those where 5 amps. per sq. ft. and temperature of 70° F. are given.

Copper deposits were obtained with current densities ranging from 30 amps. per sq. ft. to 180 amps. per sq. ft. according to duration of plating; solution temperatures ranged from 120° F. to 150° F.

We found that if the object being plated was repeatedly placed on a holder in the same position, regardless of how many times the coatings were alternated, the results were inferior to deposits obtained on specimens which were hung in different positions following brushing, buffing or plating operations. All samples tested were plated singly on a brass hook with perforations which facilitated quick change of position.

In conclusion, a consistent copper strike followed by a consistent nickel deposit is undoubtedly of much protective value. A copper flash beneath a thin deposit of nickel is not only useless as added protection, but seems to reduce the protective value of the combined coatings.

We have not aimed at originality in this paper, but have tried to record facts as they were revealed. Furthermore, the statements made are not conclusive. We are continuing tests and experiments.

CHAIRMAN GEHLING: Now, members, I think we can afford to allow, on a paper of that sort, at least ten or twelve minutes’ discussion, but at the end of that time we want to cut it off because we want to get into our business session at 10:15 sharp.

MR. S. P. GARTLAND. I would like Mr. Barrows to inform us if that would be a good procedure on cast iron, to copper plate it for five minutes, brush it, and copper plate and brush it, that is, to go through the series three times, and then nickel deposit on that for say fifty or sixty minutes.

MR. BARROWS: I would say yes, if you do not use too high a current density on your initial coating. I have had experience,—I remember one instance in particular, in gas engine cylinders. This was some time ago. They were having considerable trouble with gas engine cylinders. It seems the procedure at that time among job shops in particular was quite contrary to the procedure which we were employing, and repeatedly met with failures, and they turned the job over to our firm, and we attempted to go ahead with it, and by employing a copper solution of low density,—in fact, I believe at that time we only used a hydrometer, and I believe the hydrometer reading was something like three or four, never exceeding five, and using a rather low current density, we had no difficulty at all. And some of those cylinders are in use today.

MR. PHILIP SIEVERING: I would like to ask Mr. Barrows what procedure he took in cleansing the metal before plating,—scratch brushing, pickling, or otherwise, in order to get the pits clean.

MR. BARROWS: This material was a very, very soft sheet steel. It was not purchased for finishing by nickeling; it was purchased for a second grade enamel job, and was not really intended to be used for electroplating at all. But they were forced to turn out several hundred thousand pieces with a nickel finish, and the job was turned over to me, and I bumped up against this pit proposition. As the stock came to us from shearing and stamping, it was racked and run through a soap solution, just briefly, through an electric cleaner composed of one of the common metal cleaners, this bath being maintained as near boiling as possible,—taken from the electric cleaner and plunged into a 4% solution of sulphuric acid and water, rinsed, hung in a cyanide bath, and then if copper was to be the next operation, copper plated. There was no brushing. Although we did tumble some of the pieces toward the latter part of the work, just briefly. That was before putting in the electric cleaner or the soap. In fact, we then omitted the soap. It was just passed through a dilute hydrochloric acid, rinsed and went directly into the nickel. The ”skin,” as we call it, was not removed from the metal; and it was very, very thin,—there were no polishing operations.

MR. KREIDEL: I would ask whether using a higher amperage, higher voltage,—higher density all around, would be a better protection on a short duration. I believe it is common practice for at least job shops to use a higher current density for the strike.

MR. BARROWS: 180 was the highest we went. That was just a brief strike, 5 minute strike, generally around 120 or lower. About 32 or 4 volts, at the tank.

MR. F. HAUSHALTER: I would like to ask the gentleman who just spoke there on copper solution used on cast iron cylinders, with a hydrometer reading of 4 or 5, —well, that kind of leaves us in the dark. The thing is, what was the copper cyanide, or the carbonate?

MR. BARROWS: That was some years ago, before I had used anything else other than a hydrometer. It was made up from copper carbonate.

MR. HAUSHALTER: There would be a difference, you know, in the metal content in that, using copper cyanide.

MR. BARROWS: It was a copper carbonate solution.

MR. C. J. WERNLUND: I would like to ask Mr. Barrows what is the minimum weight of copper plate you would recommend under nickel for a good quality plate?

MR. BARROWS: I couldn’t tell you; we haven’t gone into it. In fact, this work was done simply to get this job finished satisfactorily, and a great deal of data that I would have taken, had I been preparing a paper, or had any idea of preparing a paper, I should have included, was neglected. But I had no intention of reporting anything like this; I simply picked this up from data that I casually obtained as I went along. But to my way of thinking, I wouldn’t be afraid of getting too much. Not on a line of work such as this. My firm ships goods to practically all parts of the British Empire, Japan, China, Straits Settlement, New Zealand, Fiji Islands, and elsewhere. In fact, we are now going into the European markets, and we have to meet a great variety of climatic conditions.

MR. FEELEY: Do you feel that there is greater security in the direct deposition of copper on the steel than you do the nickel?

MR. BARROWS: I don’t say that, no sir.

MR. FEELEY: Because I know from job shop experience for many years we always copper plated cyanide until some six or seven years ago Dr. Blum happened to be in Montreal, and drew our attention to nickel plating, and in our bumper work of course it is a job shop proposition of quality,—we generally deposit half a thousandth of nickel and about two thousandths of copper, and buff on the copper and put on a thousandth of nickel. And I can safely say that we are having wonderful success from that.

About eleven years ago, prior to that, we did copper plate; we ran around two and one half to three thousandths at that time from cyanide copper on steel, scratch brushed a couple of times, and then we silver plated, when we were doing any silver plating, and then we silver plated the radiator shells, silver plated bumpers, and burnished them. After eleven years in Montreal, we still have some radiator shells that had been silver plated along that line, and are as good today as they were at that time.

MR. BARROWS: I don’t even claim that the method that we found successful is practical; in fact, I wouldn’t consider it practical in our own plant; I wouldn’t attempt it. But (and this is not presented with the idea of making any claims or anything like that) we just simply present the paper as a record of what we have done.

MR. FEELEY: How would you handle that same job if you had it to do over again tomorrow?

MR. BARROWS: I would use alternate coatings, but I would endeavor to get thicker deposits as I went along. In fact, we did that along towards the latter part of our work. It was a little too frequent, that stuff. In fact, after we found how we wanted to do it, we did it in the sheets, instead of using the pieces. We went so far in the sheet and then cut it. That did leave the edges with less protection, but due to the fact that the piece was more or less protected at the edges, we got away with it; at least we hope we did. We don’t very often try to do anything like that.


A. E. S. PAGE
Assembled Expert Scraps With and Without Significance

Do you know that:
We mailed 1600 copies of the MONTHLY REVIEW last month?

Do you know that:
This page will soon be devoted to the activities of the Platers Classes, the Research Committee, the Board of Education, and the new ideas you are going to send in to increase the prestige of the A.E.S.?

Do you know that:
Our constitution lays down hard and fast rules regarding our officers, both in the Supreme Society and in the Branches, but allows each individual member the privilege of shaping his destiny without any ”do’s” or ”do nots”?

Do you know that:
Each member owes a moral obligation to the Society and although we have no oath of allegiance to bind us, we are in duty bound to boost our Society —attend the meetings—pay our dues promptly—help the other fellow carry his burden—and give our employer the best that is in us?

Do you know that:
A number of copies of the REVIEW are sent to London, Birmingham, Sheffield, and other parts of England; and that the Canadian Bureau of Mines wrote the Editor last month saying, ”We are most desirous of keeping this valuable file intact”?

Do you know that:
During the Round Table discussion at the Washington Convention, a member of Milwaukee Branch related in dramatic fashion the experiences he and a number of his fellow members had in trying to start a class for platers? He concluded by saying that ”not having a definite program and a capable instructor their efforts were well nigh wasted.” With the perseverance Dan Wittig has shown it is safe to predict that Milwaukee Branch will be amongst the first to fall in line with the new order of things and will rise from seeming defeat to heights of achievement that will make our whole membership glad.

Do you know that:
“The heights by great men reached and kept
Were not attained by sudden flight,
But they while their companions slept
Were toiling upward in the night”?

LONGFELLOW.


 




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