alive&kickin
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plating tin
Hello all, I'm looking and hoping someone here can help me with a metal plating project, or at least somewhere to look for information. I'm fairly
adept at plating zinc, copper, silver, nickel, etc. What I'm having trouble with is plating tin. I have no trouble plating some objects with tin,
however, I can't seem to find any information about plating tin objects with other metals. Is it possible to plate tin? How? Any information about
metal plating on tin would be very helpful, at least it would be a great starting place for me. Thanks in advance for anyone's time and info. Hope
this is in the right place, feel more than free to move if necessary.
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elementcollector1
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Should be about the same to plate as any other metal object. What's the metal you want to plate it with?
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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alive&kickin
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elementcollector1, not the same. Every metal plating seems to have it's odd quirks about it. Metal plating is not a one size fits all type of
process. As far as what type of metal I want to plate it with, I'll be happy with anything that works. Hope someone can help, this one has me
stumped.
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WGTR
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What have you already tried, and what have been your experiences thus far? What are the problems that you're encountering?
You could try the old standby of cyanide copper. You can then plate pretty much anything over the top of that.
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alive&kickin
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WTGR, I've tried the usual, zinc, copper, silver, nickel, etc. Whatever I try, the problem is with the metal not adhering to the tin, it just flakes
off. No copper cyanide is currently available. Even if it was I'm not sure I would want to try that one anyway. With a health code rating of 4 (NFPA
704), that's a little bit on the scary side for an amateur like me. I was hoping someone might have a more tame process.
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WGTR
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When you try to plate with copper, is the copper forming an immersion deposit onto the tin? If not, then that's encouraging.
What's the history of the tin-plated part that you're trying to plate? Are you taking it directly from the tin plating bath, rinsing it, and then
putting it into the copper plating bath within seconds? Or is the part sitting out for a few days after tin plating?
What is the source of your tin? High purity tin, or from tin solder, etc? If it has some lead or antimony in it, this may cause adhesion problems
with sulfate or chloride plating baths. In that case it may be necessary to anodically etch the tin surface in sulfamic acid, clean in an ultrasonic
tank with DI water, and while the part is still wet, put it in "hot" in the copper plating bath (with power connected before putting it into the
plating bath).
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alive&kickin
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WGTR, sounds like you've had lots of experience with this sort of thing. The tin is from a very intricate and ornate clock face from the late
1800s-early 1900s. It covers the whole face of the clock, not just the numbers, size of a grandfather. It had been broken in several places and was
solder together by a previous owner. I would like to plate the whole thing. I thought if someone had already had any luck with this they might be
willing to share a working procedure. I'm thinking if I could plate any kind of metal onto the tin, I could then plate it with silver which shouldn't
be a problem (the easy part). Thanks for the suggestions, I'll give them a try and keep my fingers crossed the whole time.
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WGTR
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Woah! That's a pretty old plating! It's going to be heavily oxidized and coated by years of who-knows-what. No wonder nothing is sticking to it!
That surface is going to be a challenge to reactivate for further plating, especially since it's a tin of unknown composition (who knows what all was
in the plating bath in 1900). If it were me, after heavy degreasing in a hot alkaline solution, I'd clean anodically in sulfamic acid solution, clean
ultrasonically in DI water, neutralize in sodium hydroxide solution, clean cathodically in sodium cyanide solution, and then plate with copper
cyanide. I know it's an ugly process, but there are a lot of things that can go wrong with such an old plating. Even doing all of these steps is no
guarantee that you'll get good results.
One of the first rules of plating, is don't practice on something that's important to you, unless you can afford to ruin it. Each one of the steps
that I mentioned can be adapted by a seasoned plater, but may trip up someone who's doing it for the first time, since I'm only given an outline, not
a detailed step-by-step how-to (that would require writing a book!).
I'd suggest making a tin plating bath with weak sulfuric acid and a tin anode (lead-free solder, or whatever). Try plating over some clean copper
pipe, and then try plating from a copper sulfate bath over the top of that. See if the platings adhere.
The next thing to try might be tin plating, then polishing the plating smooth, and then heating it in an oven (or some other means to try and
passivate the surface). Then see if you can plate copper over that. It may slough right off. If so, then try different means of reactivating the
tin before copper plating, to find what works for you. That will at least give you some experience before tackling something more important, I would
think.
Anyway, have fun!
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