stainless steel questions

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

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On Tue, 21 Oct 2014 12:05:46 -0700 (PDT), 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!
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"Ed Huntress" wrote in message wrote: >1948 Pontiac

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
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Understand this. The stainless trim is the thin stuff made from stampings. Beltline molding, fender speedline, windshield trim, that sort of stuff. probably part of the grill as well.
The bumpers and doorhandles and hood ornaments are all chrome plated.
The stainless side trims are attached with mind steel screws and fittings. These rust and drool all over the stainless.
Yes, you can pound out dings and polish out scratches in the stainless pretty easily.
Paul K. Dickman

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On 10/21/2014 3:05 PM, Ivan Vegvary wrote:

If a carbon steel wire brush is used on stainless, the stainless will become contaminated and will rust.
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On Tuesday, October 21, 2014 3:05:46 PM UTC-4, Ivan Vegvary wrote:

Ask over in S.E.J.W Ernie has a lot of experience in passivating stainless steel. I think he uses Citric Acid. A very few groceries sell citric acid. It is used in baking.
Dan
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snipped-for-privacy@krl.org wrote:

I have a bottle of CA powder that I got in the canning section at WM . Says it's for canning tomatoes .
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On Wednesday, October 22, 2014 9:08:00 AM UTC-4, Terry Coombs wrote:

Thanks, I will have a look the next time I am in WM. I asked at a Shopright store and no one had ever heard of CA.
Dan
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On Tue, 21 Oct 2014 12:05:46 -0700 (PDT), Ivan Vegvary

If the trim is stainless it can be polished. Stainless does tarnish somewhat.
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