Caustic black oxide without tank immersion - could this work?November 29, 2016
Q. I have a friend who is a sculptor. She is working on this magnificent sculpture of a horse, made out of mild steel rods, welded together.
I was wondering; could she possibly have luck putting a black oxide coat on it by painting it with a solution of NaOH/NaNO3, and heating gently with a torch? I do not expect that this would produce the kind of uniform coat expected in a job shop production piece. In an art work this might not even be desirable.
Has anyone ever tried something like this?
Consultant - The Bronx, New York
A. Hi Dave. With millions of firearms black oxided and then touched up with cold blackening solutions, I think we'd have heard of it if it was practical to do hot black oxide without immersion. So I'd suggest experimenting with cold blackening.
Ted Mooney, P.E. RET
Pine Beach, New Jersey