Partial Plating

I have been trying to talk a friend into doing a partial plating job for me.
He refuses, saying that the masking material contaminates his plating
solutions. He prefers to plate the whole object, and then buff the plating
off of the areas to be left unplated.

Is he using the wrong material as a resist? Is there a resist that can be
applied which won't come lose in hot plating solution and contaminate the
works?

On Tue, 04 Nov 2003 19:16:08 -0800, in rec.crafts.jewelry "Don Wagner"
wrote:

I have been trying to talk a friend into doing a partial plating job for me.
He refuses, saying that the masking material contaminates his plating
solutions. He prefers to plate the whole object, and then buff the plating
off of the areas to be left unplated.

Is he using the wrong material as a resist? Is there a resist that can be
applied which won't come lose in hot plating solution and contaminate the
works?


You didn't mention what metal you're trying to plate, and over what. I'll
assume gold over something else, such as silver. or perhaps silver over
something else.

And I'll also assume that your friend is using cyanide based plating baths.

The problems are twofold. first, a number of organic compounds can contaminate
plating baths. In many cases, the results are not actually objectionable, since
often, such compounds act as brighteners, giving a smoother and shinier plated
surface. However, they may also change the color, and this, along with the
different look of a slightly brightened bath, is probably what your friend
objects to. The other problem is that hot cyanide (gold plating baths, at
least, are usually used hot. Some silver baths also need heating.) is an
unfortunately good cleaner. Like many strong alkalis, it will be effective in
breaking the bond that a number of potential resist materials have with a
surface. Thus some of the easy resists we might use with an acid based bath
like Rhodium, don't work well with cyanides. Fingernail polish or other similar
resists, for example, quickly lift right off the metal. Most simple tapes also
don't hold on well, nor does asphaltum varnish. There ARE resists made for this
use. They are rubber based paint-like things, and one usually puts several
layers on to get a thick resiliant layer that bonds well with the metal, and is
thick enough to prevent the solution from penetrating it, but which then can be
peeled off when done. The stuff is not easily available from common sources,
though. You'll have to go to the industrial level suppliers who serve the
plating industry. If the surfaces you wish to mask are smooth, then there is a
tape that can work fairly well. Called platers tape, the stuff is clear, very
flexible, and has an adhesive that will resist the plating bath. It's also not
cheap. made by 3M. There are no doubt many places to buy it, but the only one
I know that sells smaller quantities is Reactive metals Inc. Even then, it's
still not cheap.

I've sometimes wondered whether one of the latex type rubber paints sold for
replenishing tool handles, or sealing rope ends, or the like, might work, or
whether even just rubber cement might work. But i've not actually tried it.
Both use bonding agents to stick to a surface that are different from the usual
things that I know don't work. I just don't know if THEY will work or not.

If you only need a small quantity of this selective plating done, your friend is
probably suggesting the simplest route. The other common way to do this is
without resists, but using a pen plater. This way, you don't stop out unwanted
areas, you simply don't go over them with the pen plater, so you only plate
where you want it. Pen platers, though, don't give as even a coating, nor
usually, as thick a coating. For small areas, they can be quite effective,
though.

And before giving up, call the major jewelry tools suppliers (Rio, Gesswein,
etc), and ask them. They may have a product available that will do this. I've
not checked recently.

Peter Rowe

Don Wagner wrote:

I have been trying to talk a friend into doing a partial plating job for me.
He refuses, saying that the masking material contaminates his plating
solutions. He prefers to plate the whole object, and then buff the plating
off of the areas to be left unplated.

Is he using the wrong material as a resist? Is there a resist that can be
applied which won't come lose in hot plating solution and contaminate the
works?

I use good old "rejected, no longer used" nail polish, my wife gives me. It
works great. Never had a problem with any contamination of my plating solution.

I must add, that the only plating I do, is 24K over 18K, and I always use a cold
bath, never hot. The nail polish would not hold up in a hot bath.

Abrasha
http://www.abrasha.com

Thanks for the help. My friend does hot cyanide gold plating over silver.
He also casts in steel. He won't do pen-plating, says he's not satisfied
with the results. What I wanted him to do was a cyanide copper strike over
steel, and then gold plate over that (probably with a nickel strike in
between). Maybe I should have mentioned that, but I was looking for the
simple answers (what kind of masking material) before making the question
more complicated.