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Old September 7, 2017, 11:25 AM   #1
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White scale corrosion?

Recently, I rediscovered a pistol my grandfather left me when he passed. I was still in highschool then, my folks put it in storage, and, well... It basically was forgotten for almost twenty years.

Twenty years in a box in storage wasn't kind to it.

It's a piece of junk, as a gun. I should just toss it in my smelting furnace and melt it into slag. It's a little Rohm 22... Even years ago, it didn't fire more than half the time. But it was grandpa's, and I don't have much to remember him by.

It's covered in what almost looks like mold; I'm guessing something in the pot metal the cast the frame from oxidized, because none of the steel parts were effected.

None of the gun cleaners I've got on hand have done much to clean it up. They took the bits of rust and gunk off fine, but not this crud.

What am I looking at, sanding it down to bare metal and slopping on some liquid bluing stuff, or is there a solvent that might do better?

I know it'll never look great again, I'm not planning to do anything more than toss it in the safe, I just want to do the best I can without breaking the bank in a garbage gun.

Link to a picture of what I'm dealing with.
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Old September 7, 2017, 11:59 AM   #2
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If it's on the frame, it's likely zinc oxide. Mechanical removal is the best method.

If it's on the barrel or other steel parts ... no idea, unless it's salts from sitting in something like a leather holster.

The steel parts will take bluing.
The Zamak frame and other parts will not. You'll need to paint those.
Don't even try it. It's even worse than the internet would lead you to believe.
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Old September 7, 2017, 12:32 PM   #3
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" the pot metal..." No such thing as "pot metal" firearms. Aluminum sure. Suspect that's what you have. Very much a guess though. It might just be the finish corroding. Use 0000 steel wool and oil or a light touch with a fine brass wire wheel in a bench grinder.
No sanding, ever. That'll just scratch it.
Looks like a Rohm Model RG-14. Wouldn't bother with it myself.
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Old September 7, 2017, 12:38 PM   #4
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That is a perfect example of corroded aluminum. Nothing you can do to restore it. Treat it with bicarbonate of soda (use an old toothbrush to scrub it) then oil it. The secret is to keep air (oxygen) from it and further corroding the metal.

Also, a Rohm handgun was used by Hinckley to shoot President Reagan and others.

Aluminum framed 22 handguns were popular in those days.
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Old September 7, 2017, 12:38 PM   #5
Bill DeShivs
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Of course "pot metal" is used in firearms!
The term actually means cast iron, but it has morphed to mean zinc alloys used in later guns.
Your gun's frame is zinc.
A small wire brush should remove the corrosion. Steel wool might work.
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Old September 7, 2017, 05:17 PM   #6
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brass brush and then paint it. ceramic type paint if you want to go out.
Every tol used in the project will have a higher monetary value than the gun though.
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Old September 7, 2017, 05:25 PM   #7
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Yeah, I know the gun isn't really worth saving, I just want to do the best I can within reason for sentimental reasons.

Thanks for the advice and pointers.
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Old September 11, 2017, 12:18 PM   #8
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You might consider looking into doing a "DuraCoat" finish on that revolver after you get the white stuff removed. You'd be surprised at how well the Dura-Coat will provide a nice looking deep black finish.

Very easy to use finish, much like spray painting. If anything, I'd recommend #0000 steel wool and if that doesn't remove the corrosion, graduate up through #000, etc.

Those low end revolvers were made with an alloy of zinc, aluminum, lead, antimony and some copper. The frames were easy to cast and didn't require much heat to do the casting, so the metal may not take to any aggressive wire brushing without removing the base material.

Last edited by SGW Gunsmith; September 11, 2017 at 12:26 PM.
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Old September 11, 2017, 01:41 PM   #9
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Use a scratch brush and then paint it in your choice of finish
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Old September 13, 2017, 03:16 PM   #10
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That oxide bloom may well dissolve in citric acid. A 5% solution heated to about 140°F is pretty quick—I've seen it take all the zinc oxide and verde gris off a badly corroded case in fifteen or twenty seconds, though that was in a heated ultrasonic bath and yours may be a thicker layer—and used in conjunction with an old toothbrush, will likely clear it away fast. Just be ready to rinse in a baking soda solution to neutralize the acid afterward so you don't wind up etching the finish loose. White vinegar could also work well enough in this instance, though you may want to add a drop of dishwashing liquid to it for wetting. I wouldn't heat vinegar because of the fumes.

You could fill the pits with JB Weld, then go for the spray finish already mentioned in order to make it more uniform looking. Or just skip worrying about the pits if you want it more original, but you will want something to discourage the zinc taking up oxidizing again.
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