Which acid is best for taking off the Stainless steel oxide? So far wire brushing and tumbling in ceramic shot has not worked.

while many acids will remove it, the very nature of what make it stainless causes more chromium oxide to form upon contact with air.

What do you want it for may help to advise you...

Nitric is used to passivate stainless. Google on "passivation of stainless steel" and you'll get all the info you need.

thanks HW,
Steve, I forged some SS leaf key chains and they all came out with this beautiful gun metal grey finish, but it wasn't what i was going for,

Edited October 17, 200817 yr by bipolarandy

you may want to look into electro-polishing of stainless

When you say wire brushing do you mean by hand ? I would try a wire wheel on either a bench grinder or angle grinder if you have not done so already...?? I haven't done much with stainless but found wire wheel makes a huge difference when hand held brush has basically no effect.
Just a suggestion.
Certain stainless (I don't know what grade, but have seen sheet stainless turn orange with rust after being exposed to muriatic acid vapours) steel will corrode to a surprising degree with certain acids if not neutralized.

Do you have any pictures ? Sounds interesting to take a look.

If you want to keep stainless stainless any wire brushes need to be stainless and only used on stainless!

Just a guess but sand blasting might work, or have you tried that?
Chris