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  for Metal Finishing since 1989
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Gun bluing for small objects

I would like to hot blue a few parts and am told that I need a black iron pot to do it in. I only need the size of a couple quart pan, can I use a cast iron, stainless steel, porcelain coated or some other type of small pan on a single burner electric portable stove.

Hal DuPrey
- Schenectady, New York
2002

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If you have to ask, you can't afford it...

...the risk, I mean. Hot bluing operates at close to 300 degrees, water boils (flashes to steam) at 212. Well trained operators, using good equipment and wearing all the proper protective gear, have been killed when water got into, or was added to, the vat and blew this 300 degree caustic solution all over them. It's just not a good process for amateurs.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002

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Hal, as was stated, hot bluing can be dangerous. I have been bluing for years and would suggest you find a gunsmith in your area that does bluing. It shouldn't cost much to have a few small parts blued. The equipment isn't much, but the safety and knowledge is very much. 300 deg. caustic soda ⇦liquid caustic soda in bulk on Amazon [affil link] will go thru leather, wool, skin, bones, etc. with both the temperature burn and the chemical burn. Talk to a good 'smith and you may be able to work a good deal, with you doing the prep work and him only having to blue.

Good luck,

Ed Kay
- St. Louis, Missouri, USA
2002

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There are a couple alternatives for bluing small parts without the relative dangers of "Hot" bluing. Since bluing is essentially a non-oxygenated type of rust, it should be possible to rust those parts while restricting the availability of air. Two methods for that are to use a torch or (the easier but more time consuming) cold rust blue approach. There is also a commercial product that works as a dip that replicates the hot bluing process.

Hope this helps.

Robert E. Moloney Jr.
- Milton, Wisconsin
2007