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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 open-work 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 lacquer baked coatings, but they are not durable enough. First I need to stop the spotting....any clues?
Saint EligiusCyanide 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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Hello, Daren.
If you search this site for "cyanide copper plating onto lead", you will find some detailed info. In terms of literature references though, a solution to the problem may be that you 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 many articles, or you can start with any of the "must have" plating books. Best of luck.
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
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I want 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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Tom PullizziFalls Township, Pennsylvania |