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

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
======================
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--
Unka' George

"Gold is the money of kings,
silver is the money of gentlemen,
barter is the money of peasants,
but debt is the money of slaves"

-Norm Franz, "Money and Wealth in the New Millenium"

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

"Ed Huntress" wrote in message
...

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
================================================== =====================

Stainless steel is only "stainless" if there is no free iron on the surface
that can rust. The rust disrupts the chromium oxide layer on the surface
that is keeping oxygen away from the bulk of the alloy and lets a pit start.
This then disrupts any chromium oxide on that surface, which lets the pit
get deeper, and after a few more rounds of this you have visible rusting on
your nice shiny "stainless" steel. The usual (mil-spec) way to passivate
stainless steel is with a mixture of mostly nitric acid, like Ed said. It
will remove surface rust, other oxides, free iron, and etch the surface a
few to several 0.0001" leaving a slightly hazy finish. At room temperature
it takes up to a month for the residual chromium on the surface to reform
the chromium oxide layer that then protects the surface from further attack.
You can speed this up by baking in a dry oven, an hour at 400F is about the
equivalent of a month at room temperature. You don't have to bake, just be
sure to keep the stainless steel clean and dry for the first month after
passivation. I've never heard of using hydrofluoric acid for passivation,
only for oxide removal after welding. You can passivate with citric acid,
which will remove free iron but will not remove oxides like the bluing from
welding. I've done a fair amount of citric acid passivation, mostly on
304SS after tig welding, and did a little testing with salt water immersion
after various steps to see if I was doing any good. On freshly welded test
coupons small rust specs were visible after a few hours to a day of soaking
in salt water, but after citric acid passivation it usually required several
days, and after baking at 400F for one hour it required several days to as
long as a week before rust was visible so I was pretty happy. It was enough
for our purpose at work, without paying to send the pieces out for nitric
acid passivation and losing the surface finish. You can't polish or grind
or whatever after passivation because you might just be grinding free iron
into the surface :-). You might be able to find citric acid locally but if
not you can order 5 lbs from www.mcmcaster.com. Mix 8-12 fluid ounces per
gallon of distilled water (I just use a 10 oz cup as a scoop and fill it
almost full), heat to 150-170 F, and immerse the stainless steel for at
least 10 minutes. I'm usually not rushed and love overkill so I usually go
2-3 hours with continuous agitation :-). The solution is good until stuff
starts growing in it, which usually takes 2-6 months if you keep it tightly
sealed when not in use, then you can pour it down the drain since it is
basically concentrated orange juice. Citric acid won't affect the surface
finish at all, which is bad if you need to clean up after welding, but is
good if you want a polished surface since you can passivate as the last step
after polishing and washing.

For your trim pieces I would hand polish a few spots to see if that takes
off the rust as well as brightens the surface back up, so see if you can
avoid any strong acids that will etch the surface and make a lot more
polishing work. When you get them all clean do the citric acid passivation.
I'd probably skip the baking, or do a few hours at 300F instead of 400F just
to be paranoid about avoiding any warping, and just wait a few weeks before
getting the pieces wet with anything after the final rinse after
passivation. Of course, before any of this (especially heating) make sure
that they are stainless steel and not some kind of plated pot metal or
aluminum.

-----
Regards,
Carl Ijames

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

"Ivan Vegvary" wrote in message
...
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

On 10/21/2014 3:05 PM, 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


If a carbon steel wire brush is used on stainless, the stainless will
become contaminated and will rust.

On Tuesday, October 21, 2014 3:05:46 PM UTC-4, 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

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

wrote:
On Tuesday, October 21, 2014 3:05:46 PM UTC-4, 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

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

I have a bottle of CA powder that I got in the canning section at WM .
Says it's for canning tomatoes .

--
Snag

On Wednesday, October 22, 2014 9:08:00 AM UTC-4, Terry Coombs wrote:

I have a bottle of CA powder that I got in the canning section at WM .
Says it's for canning tomatoes .

--
Snag

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

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