On Tue, 21 Oct 2014 12:05:46 -0700 (PDT), Ivan Vegvary
wrote:

1948 Pontiac
All the trim is supposed to be stainless, not chrome. Does this mean that the tarnish and rust can simply be polished out as opposed to expensive re-plating?
I thought stainless is not supposed to rust.
Please enlighten me. Thank you.
Ivan Vegvary

Hey, my parents had a /48 Pontiac. It was the first car I remember.
Then we got a /55 Star Chief, which was the same color as the one that
Speaker Boehner wears on his skin. That's why I call him Star Chief.
g

Regarding stainless, if it's rusting, it either wasn't passivated
right in the first place, or it's not a very corrosion-resistant
grade, or it's spent its life exposed to salt air or really foul
industrial pollution. It can also happen in oxygen-deprived
environments, like screws in a wooden boat, but that's not likely on a
car.

When you have rust on stainless, it's because the chromium oxide layer
on the surface didn't protect the iron underneath. You want to remove
the rust and eat into the iron a bit so the surface is left
chrome-rich. That's usually done with hot nitric acid in production
("passivation"), although I'm told it can be done cold with
hydrofluoric acid. I have no experience with the latter. Both are
really nasty.

Immersion in cold muriatic (dilute hydrochloric) acid will remove the
rust but it's very slow attacking the iron, and it is not good for
stainless if you leave it on for more than a few minutes. Still, it
may do the job and you can get it at any hardware store or masonry
supply. It leaves a very dull, smutty surface if you leave the
stainless in for a long time.

Once the rust is removed, it will polish out with Dico Stainless
Buffing Compound, on a power buff. What you get will depend on how the
rust was formed and how you got it off. It can work really well.

I wouldn't try to passivate it after polishing. Just hope that you got
the source of the rust, wax it good, and don't let rust build on it
again.

Good luck!

--
Ed Huntress