Removing copper plating.......Help!

[Coltsaa]

Anyone know the best way to remove the base copper plating under nickel used on most handguns? Up until now I have been having good luck soaking the parts in nickel remover which turned the parts a black color which when washed left the metal free of nickel and copper. I just ran into a Colt made in the 60's that the stripper dissolved the nickel but left the copper untouched. Mixed fresh solution and same results.
I am fairly new to this plating process(bright nickel finish) but have had excellent results thanks to Caswell! I have a power supply from Caswell if elecro-stripping is what I should be doing. Whats the best way? Any advice will be greatly appreciated!

I used the search function but didn't find what I needed.

[wop1969]

I am pretty sure you will need to use electro strip to get the copper off, that is what iI do with my pickle tank to remove copper.
just connect the negative to the anodes and the positive to the work item it should take about 1 amp for every square inch that the part is, at least that is what works for me just be carful not to leave it to long it can start to etch and dissolve the part

One thing to remember electro stripping copper will put a good buildup of copper in the tank and on the anodes so make sure you clean the anodes well after each strip, and if you do it allot the tank will copper plate things that are dropped in without any current going to the item, its like the fluid gets impregnated with copper particles and if you using a pickle solution like me i have noticed that my tank has turned into a batter i can drop a part in and produce 1 10th of a mA so that is why it will copper plate you part but i don't think that will happen over night it has taken allot of copper stripping for my tank to get to that stage.
anyway good luck let me know if I can help some more.

[dadkar2]

I have some suggestions but not a direct answer for you.

In the printed circuit board fabrication industry there are various materials that are used to etch away copper. One is ferric chloride, but unfortunately that one will attack steel. Another is ammonium persulfate. It is also used as a polymerization initiator in polymer chemistry.

I believe you can get it at Radio Shack or Frys. It's worth a try and is not expensive, but don't try it on a valuable hand gun. It will definitely etch the copper. The question is, what will it do to the steel. You must find that out before trying it on valuables.

I would try it for you, but my shop is down until Nov 1.

My personal experience with electro stripping has been dismal. I am very particular about the quality of what the stripping process does to the substrate (usually steel), so I realize I may be ultra conservative. But I have never successfully electro-stripped a delicate part without substrate damage, however minimal. I've tried various pickles and current densities. It's very difficult to control the process precisely.

Have you simply considered light sandblasting with a 320 grit or finer aluminum oxide? It will be slow, but the side benefit is it will safely clean any rust pits that might be present as well.

Kind regards,
Ken

[Coltsaa]

Thanks all for your time replying to my question! I ended up bead blasting and then buffing the remaining copper. Plating turned out great! I guess there is no substitute for good ole' elbow grease I was worried about degredation of the substrate as this was around 80 yrs old and in above average shape.

Still learing but having a blast! Thanks guys!

[dadkar2]

Great to hear of your success. There isn't any substitute for elbow grease, and no better way to remove old plating and rust than to use bead blasting.

Ken

[sross]

Coltsaa-

Judging from your logon I am guessing you are working on those types of revolver. That is what I am doing.

However, I did one in electroless nickel, so never had to put copper down first. Are you finding copper under the nickel layer in a factory plate job?

The reason I ask, now that I have messed with the pnp nickel, I am less than pleased. Electroless appears (maybe just me) to be both whiter and brighter. And, you can harden it in the home oven after you're done.

Seth

[Coltsaa]

Seth, I have been finding copper under the nickel/gold plate on alot of the SAA's. Have been using nickel remover which has turned the nickel black and washes right off taking the copper with it. Recently ran in to a second generation that the nickel came right off but the copper looked like new. Was hoping there was an easier way to remove the copper without chancing deterioration of the metal. Lots of polishing on the trigger guard to remove the copper completely.

I haven't tryed the electroless yet but am ordering a kit very soon! Glad to hear that you like it and it works out good for the SAAs. Had to start doing plating in house due to always getting plating back with missing screws etc. You know how time consuming and expensive it is to chase down 50 -100 yr. old parts. So far I am extremely impressed with Caswell's equipment.

[Coltsaa]

One other thing Seth. I suspect that the copper is used to avoid a lot of labor in the final polishing stages. Do you agree?

[dadkar2]

Steel can be polished with the white compound, but there's no mistaking that the copper polishes easier and to a higher luster.

Kind regards,
Ken