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Letter 102
Cyanide Copper plating vs. Acid
Copper Plating
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Can someone tell me the practical differences between Cyanide
Copper plating and Acid Copper Plating. I have a line of Cast Bronze
designs about the size of a lady's Broach pin (that has openwork
throughout), and I am trying to Bright copper plate over nickel.
My plater tells me that he is getting spotting from areas of my
original bronze castings which suck in his plating solution, and when
the piece is dry, the areas which have the porosity slowly release
the cyanide copper solution causing discoloring (spotting) in those
areas. He thinks that the porosity is the problem, and that I should
try someone who does Acid Copper plating. All I know is that acid
copper usually plates thicker and maybe less bright, but is there
something about the cyanide that would cause this to happen?? Will
Acid copper be an improvement ??
Also what I am doing is bright copper over nickel over the bronze
castings. I am also trying to get a clear enamel coating baked over
this to prevent oxidization. Is my plater right about the spotting??,
and are there finishers who do this kind of three step process??? I
have used laquer baked coatings, but they are not durable enough.
First I need to stop the spotting....any clues ??
Saint Eligius
Cyanide solutions are difficult to rinse and are more prone to "spot
out" than acid solutions. They deposit a more even plating thickness.
And acid copper can't be used on materials that come substantially
ahead of it in the emf activity series because it will immersion
deposit, leaving a powdery non-adherent plate. That covers the
principal differences, and I agree with your plater (and applaud his
honesty) in suggesting that acid copper may be the way to go if you
can't reduce the porosity of the castings.
Be prepared to answer whether your parts are barrel plateable or
must be racked, then contact the
plating shops listed in this
directory. Your problem is not a special or unusual one and many
jobshops can solve it for you.
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Ted Mooney, P.E.
finishing.com
Brick, New Jersey
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Wondering if you can provide detailed information on, cyanide
copper plating of lead. Web sites, text books, articles etc. I've
been searching for some time and am only finding info. from Dupont
etc.
Daren McCann -
- Lewiston Idaho
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The problem may be, Mr. McCann, that you just need to
divide your question about cyanide copper plating onto lead
into two parts: cyanide copper plating, and plating onto
lead. Once you do that you'll find some articles, but you
can start with any of the
"must have" books.
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Ted Mooney
finishing.com
Brick, New Jersey |
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Iwant to know if the acid copper overcome the problem of
pores in the zinc die-cast.
Mohamed Basiony
- EGYPT
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Your strike plate before acid copper is more important in
getting a good initial deposit in the pores that will
eventually fill with electroplated metal, such as are
present. Some porosity will not be filled in by the plating
process.
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