Removing copper plating
Got a Colt SAA in for restoration, non factory nickel plate over a pitted & buffed frame. Stripping the nickel easyÖ under the nickel plate .. copper plate, Ni stripper wonít touch it. Need a way to strip/dissolve the copper without too much damage to the base metal.
I'm not sure how it would work in stripping an entire action, but the stronger ammomia based rifle bore cleaners will remove copper from just about anything and do not seem to harm the underlying steel if you are careful with your timing and neutralization. So, if they work, I would guess that a strong ammonia solution would be effective.
Available ammong the household floor cleaning potions
That will disolve copper but not steel.
Just check there is no soft soldering or braze anywhere as ammonia will also eat tin, zinc and to some extent attack lead. It also eats aluminium.
do your stripping outside or in a really well ventilated place, you won't enjoy a whiff of ammonia.
Keep checking progress. a succession of baths in just enough fresh solution to cover the gun will work faster than one long stay in a big deep bath
The ammonia will also do a pretty good de-grease, so, once the copper is off, rinse the gun in a stream of really hot (pref boiling) water, dry it and and get some oil on it to avoid rust.
Update; Sorry Ray, we must have been typing at the same time.
It just shows that great minds think alike, and at the same time.
If there is a "blueprint" shop near you they might sell you a little jug of the REALLY strong ammonia. But, as Keith said, use only in a well ventilated area (outside is best) and don't smell it to see if it is really strong. Don't ask me how I know not to smell it.
Copper, etc. can be electrically de-plated (stripped). I don't how much trouble that is, check with a plating shop.
My plating company uses a chromate dip for brass and copper. It won't hurt the steel.
Thanks for the feedback
So regular old house hold grade ammonia eh ??
What about Sodium Hydroxide? Iíve used that in the past to remove Zink plating from screws, will eat the heck out of Zink but wonít touch the steel.
Years ago Radio Shack sold ferric chloride for etching circuit boards, I used to have a bottle of it, it worked very well. I don't know if they still sell it. I don't know it's effect on ferrous metals so I would suggest a test before dipping some thing nice in it.
Sodium Hydroxide will attack copper, but Ammonia will do a better and faster job: Ammonia actually forms a complex with the copper. You'll see that as the solution turns a really strong blue colour. I would avoid any chlorides. They tend to cause persistant rusting, and with acid conditions (the salts of strong acids, such as sulphuric, HCl, Nitric, and weak bases such as iron and copper are acidic. Salts of strong acids and strong bases e.g. sodium chloride are neutral, weak acids and strong bases give alkaline salts e.g. sodium or potassium carbonate) Anyway, back to acid conditions: rusting can only occur in acidic conditions, and as iron is more reactive than copper, it would be the gun which would corrode, not the copper plate. Go for ammonia Keith
Use Outer's Cop-out
Outer's makes an electronic bore clearner, which essentially plated lead or copper from the bore onto a rod. Instead of paying $100 for their unit, I have made several for myself and friends using a dc power supply anywhere from 3 to 9 volts. Works like a charm, and get all the metal from the tiniest crevices! Just submerge the parts in a bath of the Cop-Out solution, attach one lead to the part, and the other to an electrode in the bath, but not touching the part. The copper will plate out onto the cathode rod and look like shiny black paint. Wipe the rod down every few minutes for better cleaning.
Cop-Out is avaialble by the quart from Brownell's and Bass Pro
Originally Posted by MDH
No!! ... House-hold Ammonia is about 5%. Use 10% Ammonia, which can be found at an Industrial supply store. This Ammonia is used for industrial cleaning. That's what they normally use for bore cleaners.
Ferric chloride is used by by damascus steel or patterned steel makers (knives and such) to etch the steel to bring out the patterns of the layered steel. It will etch the different steels at different rates.
First of all, thanks for all the input. Looks like I got all the plating off; started out with Brownells nickel stripper, followed up with diluted acid, and finally an overnight soak in ammonia.
They are pretty clean; Iíll throw the parts into the bluing tank, any remaining nickel/copper will show up pretty clearly, then Iíll polish them off.
So thanks again, lots of good advice.