Stripping copper plating from brass?

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!

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,

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.

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,

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.

Q. Can you give me the name of the process to strip copper from brass that Macdermid supplies?