On 2008-01-15, Christopher Tidy wrote:

What acid do you use, Igor?

Muriatic.

I have a jar with muriatic acid and I just put stuff into that jar to
derust.

After it is derusted, I would take the piece out, wash it with hot
water, dry it quickly (I like to put small things on the electric
kitchen range to boil water off, but no more). Then, after they cool,
I put some oil on them to prevent further rusting.

I've read that the black oxide layer left by electrolytic derusting
actually sucks for painting on because it has a significantly
different coefficient of thermal expansion to that of the steel,
causing it to flake off. But I haven't put it to the test yet.

I did not like the electrolytic derusting process, too much. Acid is
more straightforward.

i