Chrome and Nickel Removal Question (long)

[bentley86]

Howdy,

A pistol has been handed down to me from my father, who got it from an uncle. It's an odd WWII bring-back, a 1912 STOP pistol, the personal sidearm of a vanquished German officer (at least that's the official family history). Well, it seems that sometime in the 1960's someone in the family thought it'd be great to chrome plate it. They didn't do a good job. It's too thick in places and too thin in others. The chrome and nickel have bubbled off in places, letting rust form on the bare steel. Being as I'm the family firearms collector, I want to return it to a more original condition.

The plan is to remove the chrome and nickel and rust blue it. I've done some pistols in rust blue and it's just fantastic, and probably what they used in Austria-Hungary back in the 1920's. I called the plating shops around here to see if anyone would take it and remove the chrome/nickel and they wouldn't. They won't deplate firearms unless they plated it in the first place. Tried sending it off to a company that specializes in firearms plating and de-plating, but they won't take it unless they can put the new finish on, too, for a very pretty penny.

So, I decided to do it myself.

I made a 25% sodium hydroxide solution and used a 6V battery with light bulbs to control the amperage for the small parts and a 12V battery for the much larger pistol frame. The forums here were a great help in figuring it all out.

As I picked up from reading this forum, chrome is a blue-silver color and nickel is more yellowish. So I deplated the chrome, seeing the yellow solution form around the part and then stop. I took the part out and sure enough it was yellow-colored. Dried the parts and got it ready for removing the nickel.

I used B-9 Nickel Stripper. Pretty straightforward to make and use. Put the parts in, kept the solution at about 140 degrees and kept swirling everything around. I was using a 2-gallon pot on an electric stove, but only making a quart of stripper at a time. All the parts formed a black smut. I rinsed them off, dried them and carded off the smut with a wire brush on a dremel tool.

There was still a layer of nickel, though much thinner. Fine, I thought, I'll put them back in and get it off. Put the parts back in and spent 20 minutes swirling around. No black smut formed. Thinking I'd used up all the stripper, I made a fresh batch. I spent another 30 minutes swirling it around with no smut forming except in a few small places.

Perplexed I looked carefully at the parts. They were now the blue-silver color of chrome. But surely that couldn't be. Where did this fresh layer of chrome come from? Could the plating on the gun parts be steel-nickel-chrome-nickel-chrome? Can you plate nickel on top of chrome? And then chrome on top of that?

And if it's not chrome, why would the nickel stripper stop working? I made it the same way both times and kept the temperature about 135-145 degrees.

And if it's chrome, did I contaminate the nickel stripper solution with hexavalent chromium?

Any advice would be appreciated.

[bentley86]

I made another batch of nickel Stripper and tried it again tonight with a couple of pieces of nickel-plated metal as a control. The stipper is working and the other pieces of metal had the nickel off in short order. I'll try reverse-plating this new layer of chrome off sometime this week.

[moto-chrome]

Gee I find it hard to believe anything would stick to chrome. In any case I think chrome is so easily removed without power. Just soak 5 to 10 minutes in pickle #2 (2 parts water 1 part hydrochloric acid).

[fxstcguy98]

Nothing will plate over chrome. Are you sure that is not just stainless steel.

[bentley86]

Okay, chrome can't be plated over, which makes real good sense.

I don't want to use hydrochloric acid as all the parts have exposed steel in patches and I don't want to harm the original steel. The steel is not stainless. This is definitely a plating that looks like chrome. I thought that maybe my bath was not working so I use it on a small chrome plated button. Took the chrome off in minutes. So the bath is still working.

I tried reverse plating a small gun part a few days ago and it still didn't work and I left it in the bath for about an hour. No change. I tried the nickel stripper on it for 30 minutes and nothing.

Okay. Are there metals other than chrome and nickel that someone may have tried in plating an old gun? Maybe it's something else.

[bentley86]

Okay, final update.

Just out of sheer frustration I put everything back into a fresh batch of nickel stripper and let it cook at about 140 degrees for about 4 hours. I didn't see any new smut forming, but I was nearly constantly swirling the pot. There was black stuff floating in it after a while so it was slooooowly working.

After 4 hours it appears that I am down to bare steel. I think that it was just a thick layer of nickel that was just being real stubborn.

I've polished the metal and it looks real pretty. Now it's time for the long and tedious rust bluing process.

Thanks!