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MONTHLY REVIEW—Part 2

Published by the American Electroplaters Society

Publication and Editorial Office, 3040 Diversey Ave., Chicago

VOL. XVI   JULY, 1929   No. 7

Click here for Part 1.


DR. W. BLUM

*Philadelphia Branch, 1929, Sovenier Sov-year Book.

Bureau of Standards and Member Balti.-Wash. Branch,
Electro Plating Research at Bureau of Standards, Washington, D. C.

DR. WM. BLUM: I don’t know whether to consider that being placed at the end of the program is a compliment or not, but I will let you judge afterwards for yourself. At least, I can’t help but be reminded of the time when I attended a Chicago banquet. This was before they held the afternoon educational session, and the speeches then were following the banquet in the evening, and I happened to be down as the last speaker. But I also happened to be down to take a train at 11 :30, and the result was that it was - eleven o’clock when I was called on to speak, and I spoke, I think, for about ten minutes, grabbed my hat and coat, got in a taxi, and’ got off to the train. About a month later, I met one of the fellows from Chicago, and he said to me, ”Say, Doc, that was the finest talk you ever gave. I hope you always have a train to catch!”

Now there is one difference between this talk that I am going to give you and the one which is reported in the reminder, the Quaker City Reminder, and that is that when you get to the end of the Quaker City Reminder you know what the man was talking about. I am not sure whether you will be able to say that you know what I have been talking about when I am through, or not. As a matter of fact, my talk is a continuation of the Question Box, because I am not going to tell you the answer to these things. If we know the answer, we would be through; But I am going to tell you some of the questions that we are working on at the Bureau of Standards so that you may be better acquainted with the progress which we are making or trying to make.

This resume, then, of the work which is in progress at the Bureau is not intended to be a final report on any except possibly one or two of the subjects, but rather to let you know what we are interested in so that you can inform us and advise us regarding any information that you may have which will assist in these researches.

Now in spite of the fact that everybody is interested in chromium plating today, as we heard in the discussion a few minutes ago—nickel plating in connection with chromium plating has certainly received more importance even than before, and while as also pointed out in the discussion, the pH, the acidity of nickel solutions, or any other single factor, is not sufficient to account for either the pitting or the peeling of nickel plating, it is a factor which must be controlled in order to produce uniform nickel plating. Now of course many of you are familiar with, and have used the Colorimetric method of measuring pH and controlling the solution. Within the past few years there have been two or three persons who have suggested and recommended the use of the Electrometric method, the so-called Quinhydrone electrode, for measuring the pH of the nickel solutions, an apparatus possibly more elaborate than that used for the Colorimetric, but on the other hand, which gives very satisfactory, reproducible results. Now one question that has come up is the fact that sometimes the results obtained by the Colorimetric method and by the Quinhydrone method do not agree. Some persons say they find they do agree; others find they do not agree. In order that we shall have the facts, and afterwards we can explain them, we are making a co-operative study with four or five laboratories besides our own, in which a whole series of nickel solutions will be measured by these different persons with different indicators and with the Quinhydrone electrode so that we will find out if there is a consistent difference in the results obtained by the different methods. In other words, the thing that I want to emphasize to you platers is this, that we are not satisfied to get a method. That is the first step. Then, afterwards, we have to refine that method, we have to determine whether it is sufficiently accurate for the increased demands that are being made upon it through, for example, the developments in nickel plating.

Another little detail in connection with nickel plating is the specification of nickel salts. We have nothing new to offer on that, but to call your attention to the fact that although heretofore we have just proposed a specification for the use of those in the industry who cared to use it, we are now drawing up and will very soon adopt a specification, a Federal specification, for nickel salts, which will mean that all of the nickel salts used in electro-plating or electro-typing establishments by the Government, that is, of the Government, will conform to this specification, and the interesting thing is that in corresponding both with the manufacturers of nickel salts, and some of the very large users, we have found that except in minor details, the specification which was proposed five years or so ago seems to meet all the requirements. Again, the net result of that is that the manufacturers will automatically tend to bring all of their material up to that standard because they can’t afford to make one barrel of salt for Uncle Sam a little purer than the rest of their stuff, and they are going to try to live up to that standard, which I believe most of them are doing at the present time.

We are working on the purification of cyanide in order to make a study of cyanide plating solutions, and feel that after a great many trials in the very difficult process of making an absolutely pure cyanide as a standard, we have succeeded in doing that.

Copper electro-typing solutions may not-seem to be of interest to you, but we are working upon the use of addition agents in copper electro-typing solutions, and especially the means of controlling them. Now here is the significant thing, that in connection with electro-plating today, there is no question that acid copper solutions are being used to a far greater extent than they were, for example, ten years ago, and therefore anything that is learned about copper electrotyping solutions will, with proper adaptation, be useful also to the electro-platers.

We have been doing some work with iron deposition. Again, this may not be of interest to most of the platers. It is information of an electro-forming proposition, but it points out the possibility in case you have a problem of that kind come up. As you all know, we have for several years been carrying out at the Bureau of Engraving and Printing an electrolytic procedure for making the printing plates which are now used for printing over 70 per cent of the paper currency. Now those plates have as the essential part, nickel and copper within a chromium surface. We are experimenting, and I think I can say successfully, upon the production of all iron plates. In other words, deposit a plate a quarter of a inch or a fifth of an inch thick, entirely of iron, and then to put chromium upon that surface. That would have the advantage of not only using a cheaper metal than the nickel and copper, but also the fact that we have a soldering process and several intermediate finishing processes. Those plates are not in production; that is, we are not printing very much money from those iron plates, but the results obtained so far are so promising that we feel reasonably certain we can work out the details so as to put it into actual operation.

I just brought along a few samples of the iron. That (shows) represents a sample of the iron that is cut down to make a test for tensile strength. This other piece (shows) you, as you can tell by putting those two pieces together, that there is a considerable elongation of the specimen in the processes of pulling it, determining the tensile strength. In other words, this iron is a relatively soft, ductile iron. I don’t mean it is very soft; it pro ably is about as hard as the average nickel, and has an elongation of about 20 per cent.

I am going to take a minute to tell you an interesting experience, because it is good just for us all to once in a while recognize our mistakes or oversights, if you choose, and you can judge afterwards whether the joke is on me or on Tom Slattery. I think we both have to share it. He was making these iron plates at the Bureau of Engraving and Printing and getting some excellent results with the flat plates which will represent about a fourth of the production. The question came up, would it be satisfactory to make these flat plates of iron for curved plates.. They would have to be curved after they were made. And since everybody talks about electrolytic iron as being brittle, and since in our first experience the iron, even though it was satisfactory, was somewhat brittle, he, and I as well, naturally thought that we would have to do something to make it soft enough to bend, so he asked if we could make some tests on annealing iron, and he sent these samples out of which the one I showed you is one of the pieces, and we determined the tensile strength, and the elongation of one specimen was determined while we were going ahead with the annealing experiments, and when I got the result that the material had over 20 per cent elongation, it occurred to me that a material that was stretched 20 per cent doesn’t have to be annealed in order to bend it around to a curve. So, one of the pieces of iron was lying on my desk, and I took it and bent it around (demonstrates). As you can see, there is no question about it being brittle at all, and the joke was on us. In other words, we were trying to remedy a defect which didn’t exist in the material But it just shows we mustn’t take things for granted.

All of us get these old woman’s tales, as I call them. In other words, these ideas that somebody handed down from somebody else, and so on, and we believe them instead of taking the time to find out for ourselves whether they are so or not. That is a good lesson for all of us.

On the question of chromium plating, there are lots of unanswered questions, of course, and some of those have come up and have been referred to in the discussion this afternoon. We are trying to fill in the gaps in chromium plating; in other words, to get information on those important points on which there is still uncertainty. One of these is regarding the whole process; in other words, what is the theory of chromium plating? Why is it that you have to have sulphate in there ? What is the effect of trivalent chromium, that is, partially reduced chromium or chromium chromate, in the solution? In going at it that way, we are starting out with a study of conductivity, and then will determine the effect of these different things on the conductivity. First of all, of course, we have to know the conductivity of the pure chromic acid, and that means you have to make some pure chromic acid. The chromic acid which is being furnished to the trade today for chromium plating is remarkably pure. I say that without any hesitancy. -But at the same time it was necessary to get it down to the highest degree of refinement which has proven to be a quite troublesome thing. Then we will be ready very soon to measure the conductivity. Because this is a surprising thing that in all of the literature of chemistry, that is, of physical chemistry and conductivity, you can not find any reliable result for the conductivity just of pure chromic acid. Someone called our attention to some results in the literature which we had overlooked. They were buried in a place that we didn’t expect them, and when we took those results and compared them with a few other results that we had located, we found they differed by 50 per cent, so that they can’t both be right, and we are hoping to find out which is right, and get the facts—so that there is one of the by-products; in other words, we will get a table of the conductivity of pure chromic acid as something to be published in the literature and then we will use that information to see how we can help out with chromium plating.

We have heard a good deal about throwing power in chromium plating, but as far as I know, no actual measurements, quantitative measurements of throwing power in chromium plating have been published, and Mr. Farber, who is research associate of the Electro-Platers, has started this study of throwing power. Here again, it proved difficult, because we had to get a throwing power box— you all remember the hard rubber box I have shown here several times, but hard rubber will not stand up any length of time in the chromic acid, and it was necessary therefore to make a plate glass box without any cement, in other words, a plate glass box which will be tight without seams. We succeeded in doing it, but it was a very troublesome thing to do. Now then, when we started to make the measurements, I was surprised—perfectly frankly disappointed to find how difficult it was to get quantitatively reproducible results with chromium plating. Of course, we can get good plating over a certain range of conditions, but to try to get exactly the same efficiency in repeated experiments, especially at low current density, we found was quite difficult, and it has only been within the last couple of weeks we have got results that we believe are correct, and then we can go on and vary those, and I hope that within a few months we will have some definite information upon throwing power.

I am going to refer to a point which came up in the discussion, even though I can’t give an answer to it, and that is that there may have been some confusion in your minds with regard to the effect of iron, because it is entirely one thing to talk about what the effect of a little bit of iron may be in a solution, and the effect of a large amount of iron in the solution. In other words, we can say without argument that there is ample published evidence to show that large amounts of iron increase the resistivity of the solution, and are therefore detrimental. I do not believe, with all due respect to Mr. Proctor and others, because there are a good many others in the country that have used iron in the solution—I do not believe that there have been any very careful comparable experiments conducted from which you can say whether a very small amount of iron would improve the throwing power, for example, or not. We hope to get results on that which will be conclusive.

We have been making a few experiments which so far or recently have been promising, on chromium plating on aluminum ‘alloys. Now we all know that there is a considerable amount of chromium plated aluminum ware being produced today which is at least fairly satisfactory, which represents nickel plating over aluminum, and then the application of the chromium to the nickel, using the methods of nickel plating that have been developed by Dr. Work with the Aluminum Company. Now the particular problem which we have in mind demands application of a thick coating of chromium, not for ornamental purposes, but for wear resistance. So far, as I say, we haven’t the answer to it, but at least we are getting some promising results which indicate if we can define the conditions we can get such deposits. Our trouble is we get them sometimes, and sometimes we don’t.

One of the most important questions in connection with chromium plating has been the question of the health of the operator. Now a couple of years ago, when the question of the health hazard in chromium plating came up (it may have been in this meeting, for all I know), I rather smiled—I will be perfectly frank, I rather smiled at the idea of platers who handle thousands of gallons of cyanide, talking about anything being poisonous, because I thought that platers were all so hard boiled, or copper plated by this time that there wasn’t anything could affect them at all. And you remember’ the incident about how poisonous cyanides are—the medical student in the examination question said that ”Cyanide, or hydro-cyanide, is so poisonous that if you put a drop on a dog’s tongue it will kill you in a minute.” Chromic acid is not poison in that sense. There is no evidence that chromic acid or chromium compound produce any detrimental effect on the system. I don’t say that they don’t, because no one can ever tell what might be discovered from further research, but thus far all the medical literature fails to show any evidence that the chromium compounds produce any effect on the system as a whole. But on the other hand, all of you do know that they go after sores or cuts on the hands and produce very mean sores. You also know that they go after the nasal tissue and produce inflammation, and finally a destruction or perforation of the nasal tissue.

The question came up to us in a way which is very important to you folks and to your employers. It came to us through the State Board of Health, through these Employee’s Compensation Boards, because if chromium plating were recognized as a dangerous profession you would soon find that there might be unnecessary precautions thrown around it, that might hinder and hamper the development of chromium plating. We solicited and obtained the adoption of the Public Health Service in determining the effect of chromium compounds on the health of operators, and the investigation, which was brief, consisted in measuring the ventilation in six different chromium plating plants in determining the amount of chromic acid present in the air under definite conditions of ventilation and then examining the workmen to find out which of the men had suffered any injury to the nasal tissue. The results indicate that very low concentrations of chromic acid will, if inhaled continuously, produce injury to the nasal tissue. People who were racking up work, ten or fifteen feet away from the chromium tanks, would just as likely have perforated septum (they didn’t know it) as those who are working right over the chromium tanks. In other words, if the ventilation was poor and chromic acid got spread out into the room, it didn’t take much of it to do harm. On the other hand, it was perfectly feasible to eliminate the trouble with chromic acid if you have enough ventilation of the right kind. Fortunately, I think we can say that practically all chromium plating plants have adopted what is certainly the best system of ventilation, that is, transverse ventilation. The trouble with putting a hood over a plating tank or cleaning tank or anything of the sort, over which a man has to work, is that you let the man work there and inhale all of the stuff that he can, and then you pull out the rest. Now that isn’t doing him any good. So that the only type of ventilation that is effective is to take -the fumes out before they get up into the air of the room which it is necessary for the man to breath; and that is being done effectively in every plant, or can be, by very simple modifications. We found that with the ordinary arrangement, a slot anywhere from one to two inches wide running along the edge of the tank, that if you have a velocity of the air of about 2000 feet per minute in that slot, it will remove the chromic acid so completely there will be no injury to the operator, if the tank is not too wide. If your tank is over 18 or 20 inches wide, it is better to have a ventilating duct on both sides of the tank so that you don’t give any chance for the gas to go off and get away from the current of air, Or you can put the duct in the center, if you choose, and pull both ways. That is purely a matter of convenience with respect to the type of work to be done. If the men, in addition, will put a little vaseline in their nose occasionally, and on cuts and sores, they will very greatly reduce the danger from chromic acid. If the trouble develops, it is well to have medical treatment immediately, and one of the things which is used in that medical treatment is to put some reducing agent on. You see, chromic acid is a strong oxidizing agent. Therefore if you put a reducing agent on, such as ammonium polish sulphide, any sulphide you use in coloring, on sulphite, or thyol-sulphate, anything which will destroy the chromic acid and prevent it from continuing its attack of the tissues, after which you have the problem of a sore to heal with the proper ointments.

In connection with the chromium plating of plumbing fixtures, the Government of course purchases these materials for new buildings and so forth, and they hesitated to purchase chromium plated fixtures without a specification for them. The difficulty with writing a specification for chromium plated plumbing fixtures is that they have not been in use sufficiently long that we can really say with certainty that fixtures that are plated with a certain thickness of chromium would last so long under certain conditions of service. And therefore we have to guess at it, and, guessing, we naturally want to guess conservatively. In other words, it is better to put on more chromium than is needed in order that chromium doesn’t get a black eye in order that you don’t have a lot of failures of chromium around in a lot of installations and people say, ”We have no more use for chromium plating.” And the specification which has been proposed and probably will be adopted is that brass fixtures shall be plated either with chromium directly, with an average of .0()02 inch, or with .0002 inch of nickel plus .00002 inch of chromium. In other words, either have a thick deposit of chromium, or a relatively thick deposit of nickel and, a light deposit of chromium. We do not know,’ from actual experience, which of those will be best. Certainly the thicker deposit of chromium will stand up under the wear and abrasion better. On the other hand, it may be that the deposit having nickel and then a thin deposit of chromium will stand up under tarnish and corrosion better, because we know of course the more layers you have there of metals the less likelihood there is of having porosity all the way through it.

The question came up as to whether chromium plated directly on brass. This was a cast brass, and likely to have these hair line cracks. So far as we know, it may, but a few experiments did not indicate their presence to the same extent as was observed in the work of Baker, who found that if you put more than a certain thickness of chromium on steel, that is, which had been nickel plated, that he got an actual decrease in protective action, because of increased cracking and increased porosity. Now I say that that deserves further study, but so far on a few samples we had plated in a commercial plant, we did not find, for example, by simply taking a fixture—it is easy enough—you take a heavy chromium plated fixture and place it in concentrated nitric acid, and if there are any pores and nitric acid will find them and under those circumstances we did not find in most of the specimens any evidence of this cracking. But a couple of the specimens did. We put them in nitric acid, and they just flaked off, just whole silky flakes of chromium came off, showing perhaps under certain conditions of plating there may be more tendency to that cracking than under others.

An application of chromium plating which is perhaps less conspicuous, certainly less conspicuous than the plating on automobiles, and which you platers may not come in contact so much with is the question of mechanical equipment in other words, dies, gauges, those things which are plated not for appearance, but for purposes of wear. Now here is a difference. I just suggest this to you. If anybody puts chromium plating on automobile, that automobile is bound to cost them a little bit more than if they didn’t put the chromium plating on, but if they put chromium plating successfully on gauges and dies, they use in making automobiles, and make those parts last longer, the automobile will cost a little less to make than if they did not use the chromium. In other words, the savings in chromium plating may come from these inconspicuous uses, where the chromium is used for wear resistance. We made a survey recently, of which the results will be reported in detail to a meeting of mechanical engineers the first week in December, and that showed chromium plating is being quite extensively applied, and tried, on, various mechanical equipment. The gauges are certainly most satisfactory, plug gauges are very satisfactory, and many plants are using them in regular production now because they find that they last several times as long as the plain steel gauges. On thread gauges, the problem is a little more difficult, but that is a problem for you platers. It is possible, with proper control, to deposit the chromium (of course you can never deposit chromium uniformly on a thread gauge; there is bound to be more at the top of the threads than at the bottom), but with the study of throwing power, and with the best efforts that the platers can use, they make that difference small enough so as not to be outside the tolerance of the gauge. Then the plating will be satisfactory, or may be satisfactory, on the thread gauges.

We find that on dies for stamping sheet metal and so forth that the results are very satisfactory. On moulding dies, for bakelite, for rubber, for various materials of that kind, chromium is being used to a considerable extent, although there again (and I mention this for the benefit of the platers), the man who is interested from the standpoint of production (that is, a plastic material) said they got the most erratic results. One plant would say the chromium plating was good, and another plant would say it was no good. Now, it was perfectly evident that if they were building the same product the plating must have been different under some conditions than under others, so that is a problem the plater has to have in mind

When we come to stamping dies, where we have very high pressure and impact, the problem is more difficult, because chromium is brittle, and I can say in advance I feel quite certain that if you put much chromium on, it will not be satisfactory. But a light coating of chromium on, for example, a hard steel die, say .0002 inch of chromium, there is good reason to believe will increase the life of the dies. Had you asked me the question, I would have been more skeptical. But the experiments are being made right here in the Philadelphia Mint. You see, this is.a money making proposition, this chromium plating, and the first experiments they made, they did not get conclusive results, but within the last few months they coined some pure nickel coins for South American countries. You see our ordinary American nickels have 25 per cent nickel and 75 per cent copper. These were pure nickel, and they coined some thirteen million of them, and they found that the pure nickel, although apparently not any harder than the other nickels, wore the dies faster than the ordinary ones, and in despair they tried the chromium plating and found the life of the dies was three to four times as long with the chromium plating than without it. So we can say at least in that application, in coining nickel coins, that the chromium plating stood up. But I warn you in advance you will probably get better results with a light coating of chromium where you have a heavy impact like that, than with a heavy coating of chromium.

Another subject I will touch on very briefly, because you will get a more detailed report of it—we have already had some report on the subject of spotting out, which Mr. Barrows, your Research Associate, has been working on at the Bureau of Standards, and I just want to remind you that the evidence shows there are two different types, that which occurs on sulphide finishes; which consist of the growth of small crystals under the lacquer, and that which occurs particularly on cast metals, which is ‘certainly due to the porosity of the metal and the taking up of the solution, the chemicals from the plating and cleaning solutions, in those pores. And then afterwards it comes out and produces a stain. Now all of the evidence shows that in order for it to come out and stain, there must be moisture get in. Therefore, if you keep the moisture out, you will have less tendency for spotting. And the quality of the lacquer has a great deal to do with the penetration by moisture. We found, as has been reported already in the Review, that the phenol condensation lacquers are less porous, less permeable to moisture than are the nitro-cellulose lacquers, which you have commonly used, and are therefore probably better suited for that purpose, but they have to be baked. We are not through with those experiments; we are going to make further experiments confirmatory—and also just within the last week have invited all the lacquer manufacturers of the country—I’ll say we tried to invite all, if we have overlooked any I will ask any of you who find you have been overlooked to write to me, because we want all of the lacquer manufacturers of the country to send in samples so we will find out whether any of the products are essentially different, that is, products of one type—if they are essentially different from others. And that work, when completed, will be published in detail.

Now that covers what we are doing, what we have under way You notice I haven’t given you very much in the way of definite results because those are the questions which we can’t answer, but we hope to answer as a result of the research work.

Just what problems will be taken up next will depend upon the wishes and advice of the Research Committee, who in turn are just at the present time asking the manufacturers of the country what they think are the most important problems of plating to take up, and I simply want to tell you that we at the Bureau of Standards want to continue and extend our work as much as possible so as to make it of direct benefit to the platers and to the whole plating industry. I thank you.

CHAIRMAN SCOTT: Are there any questions you would like to ask Dr. Blum?

Well, gentlemen, this has been a very interesting afternoon, and I am sure .we are indebted greatly to all the speakers.

This meeting is now adjourned.


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


They’re Both Right

Phone Operator: ”That language is entirely uncalled for.”
Customer: ”So were the last seven numbers you gave me ”—J. Sarnat.

————————

The Remedy

”I say, old dear, what’s good for biting fingernails?”
”Sharp teeth, silly.”

————————

The stingy farmer was scoring the hired man for carrying a lighted lantern to call on his best girl.

”The idea !” he exclaimed. ”When I was courtin’ I never carried no lantern. I went in the dark.”

”Yes,” said the hired man, sadly, ”and just look what you got.”—”Ain’t so.”

————————

Here’s health to girl who can dance like a dream,
And the girl who can pound the piano;
A health to the girl who writes verse by the ream,
Or top with high C in soprano;
To the girl who can talk and the girl who does not;
To the saint and the sweet little sinner;
But here’s to the cleverest girl of the lot—
The girl who can cook a good dinner.
— (Editors Favorite.)

————————

Do You Know That

About the only time a golfer tells the truth is when he calls another golfer a liar?

Nowadays whatever is not worth saying is sung?

You can’t be a perfect idiot because nobody is perfect?

————————

The Measure of a Man

Not—”How did he die?”
But—”How did he live ?”

Not—”What did he gain?”
But—”What did he give ?”

These are the units to measure
the worth of a man, as a man,
Regardless of birth.

Not—”What was his station?”
But—”Had he a heart?”
And—”How did he play,
His God-given part?”

Was—”He ever ready
With a word of good cheer,
To bring back a smile,
To banish a tear?”

Not—”What was his church?”
Not—”What was his creed?”
But—”Had he befriended
Those really in need?”

Not—”What did the sketch
In the newspapers say?”
But—”How many were sorry
When he passed away ?”

————————

Yesterday’s Tight-Wad

The fellow who was unable to take his girl to the theater. She couldn’t find her purse.

————————

Auto-Suggestion

A sore throat is all that keeps some wives from driving the car.

———

If sulphur products are the cause of spotting out, then the cause of that cause must be our good friend, Wilfred McKeon, who is the father of sulphur products.

———

Did you notice the number of fellows looking for Dad Liscomb. He gets more popular each year.

———

H. E. Willmore was a popular guy also.

———

M. W. McKeon had as a guest Miss Joan Trumbour, assistant advertising manager of Metal Industry, in an airplane flight over city of Detroit. And when you get Joan up in the air that’s something.

———

Geo. B. Hogaboom conversed with Mike, then decided his brass was green enough and quit Mike. Our first Vice-president Van made a bum out of Mike and had lots of voice in reserve.

 

 



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