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Brush plating copper onto steel

 

Any advice on brush plating copper onto steel? I would like to plate copper myself onto sanded and buffed hammered steel to fill in the pores and scratches, buff to a mirror smooth surface, then send to a silver plating shop for the finish.

Do brush plating systems work for filling in? Do I need something like a coat of nickel on the steel first? I want excellent adhesion as the metal will be hammered some after plating.

Any help is greatly appreciated!

Keith Kropf
steel pans - Gulf Breeze, Florida, USA

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The drums you've shown us on letter 12564 are awesome! Copper (from a simple salt like copper sulphate) is more noble than steel and will immersion deposit on it even without electricity applied. That's bad because this uncontrolled immersion plateout results in a very loosely adherent powdery plating. You need to start with cyanide copper plating (dangerous, not very ecological, and unsuitable for a casual shop), or a proprietary pyrophosphate copper (available from EPI / Electrochemical Products Inc. [a finishing.com supporting advertiser], for example), or a nickel strike. After one of these you can go on to your copper sulphate ⇦ this on eBay or Amazon [affil links] based bright acid copper plating.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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Talk to your local brush plating supplier; the technology is also known as tampon plating, so you may get a better hit with that term. These guys formulate their electrolytes for various substrates as they do not use the same plating bath compositions as conventional plating solutions. Generally the solutions are much more concentrated.

However, I would suspect you may need to use two copper solutions to get the best adhesion; one being based on cyanide to give good adhesion and the other to thicken the deposit. However, perhaps there is someone out there who has another copper solution that is as good as cyanide copper.

Once the copper is down, you can coat it with almost anything, again using brush plating systems.

Brush plating is brilliant at removing dents and damage from parts as the plating can be localised to specific areas. Its just like painting with metal! Once down, the filler metal can be machined back.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

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