Ted Mooney, P.E. RET
- Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Stripping copper plating from brass?
Q. Is it possible to strip copper plating ~150µ" thick from a brass substrate?
I realize that brass (Cu,Zn,trace Pb) is a copper alloy. If it is possible, please provide a solution.
Thank You, M.K.
Mark Kruzelelectronics mfg - El Cajon, California, USA
2003
Remove copper plate from brass lamp parts
Q. Can I chemically remove or reverse electroplate an old brass oil lamp that has a copper plating over the brass?
Norman E. RoseHobby - Bumpass, Virginia
2007
A. You can use electrolytic etching process-acidified copper sulphate ⇦this on eBay or Amazon [affil links] solution as electrolyte,object=anode;cathode=copper(it can be covered with cotton wool and wetted with electrolyte too),as current source you can use 4,5 V battery or hobby drill rectifier.Good luck and hope it helps!
Goran Budija- Cerovski vrh Croatia
2007
March 1, 2012
Q. I and my colleague make the old-bronze-like treatment on brass parts;
This is the simple process: buffing & polishing, acid copper plating, black oxidation, brushing and powder coating.
And the part with defects would be stripped and reworked;
Here is the question:
the part has some precise dimensions; the traditional stripping is designed to protect brass substrate, and cannot strip the acid-copper-layer, so the dimensions are larger and larger in reworking.
Where to find the knowledge to solve this? Or a solution supplier? Thanks!
- Guangzhou, Guangdong Province, China
A. Hi, Frank. I would hesitate to call your bronzing process "simple" if you can't do it reliably and are still dealing with rejects and rework that keep making the items larger and larger; maybe it's more difficult than you realize yet :-)
You seek the holy grail of stripping when you seek a process that "knows" what part of the object you want removed and don't want removed when they are made of very similar materials. I doubt that you will find a suitable chemical solution, although electrolytic stripping might possibly work if the shape of the parts is simple and favorable.
Personally, I think you should concentrate your efforts on making your simple process more robust and reliable so you have very few if any parts to rework. Best of luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 1, 2012
Q. Ted, thanks for your replying.
Just like you said, it's not simple, I'm not very good at expressing my thought in English, -_*!
Having the question for 2 reasons:
1. the old-bronze-like order is few and the part is not simple at all;
2. I've seen a process to strip copper from brass in another workshop!
It's totally different from the traditional stripping.
The process is electrolyzing; at first the part is reacting in the tank, and the surface is turned to white slowly, just like some deposition layer. When the part is totally white, then washing the part with acid solution, the part turned to brass-like yellow.
I've been told the process is secret; the only thing I know is the technique is from Taiwan; I don't know how it works.
The brass substrate and the acid-copper layer must be different in some aspect.
I hope somebody can teach me this, or do some business with me.
Anyway, I will put my focus on improving yield rate -- do my best to make less reworking. Thank you.
- Guangzhou, Guangdong Provice, China
A. Hi Frank. Your English is very good, and I can't speak a single word of Chinese ... so thank you for your effort.
I am not familiar with that stripping approach, but it is very interesting. Thanks for telling us about it. It is possible that some other reader will recognize it. It may be a licensable proprietary product rather than a secret held by one person, or it may even be generic knowledge that I am simply ignorant of. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 5, 2012
March 9, 2012
A. Following on from the comment re forming a coating and cleaning that off, MacDermid used to offer a concentrated poly sulfide based strip that formed a copper sulfide coating which you then cleaned off mechanically, or chemically in cyanide, and then re-immersed until all copper removed. The polysulfide did not attack the brass. Slow, messy but effective.
Geoffrey Whitelaw
- Port Melbourne, Australia
Q. Can you give me the name of the process to strip copper from brass that Macdermid supplies?
Kivanc EkincilerDefence Industry - Ankara, Turkey
January 17, 2013
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