Paul,
Such a chemical exists and has for quite some time. It goes by the name Metal
Prep, Metal Etch, or any number of other names depending on the manufacturer.
Basically, it's based on Phosphoric acid, like Naval Jelly is, and it's used
as you describe, depending on the manufacturer's instructions, of course. Talk
to the folks at your local Automotive Paint & Supply store about it.
Something in your message I'm not really clear on: you say the rust is
bleeding back through the paint? Do you mean the finished, painted panel or the
primered panel? If you mean primer, you have to remember primer is not a finish
coat. It is NOT waterproof, and moisture will soak right through it and rust
will set in underneath the primer. It doesn't need much moisture to do this
either. Even a bit of dew in the morning is enough. You need to shoot a sealer
over
the primer to preotect the metal if you're not going to be painting the part
within a relatively short time. If you mean rust is bleeding back through the
paint, you're not getting all of the rust off of the metal to begin with.
Also, if you're just stripping the front side of a rusty panel and not
stripping
the back side, rust will continue to form and eventually eat through both the
metal and any finish you apply.
I've never used POR. I'm a bit hesitant to try something you brush on over
rust. I mean, you're trying to get rid of the rust, right? Why cover it up to
make it look better while it's still eating away at the metal? No thanks. I'll
stick with good old sandblasting/sanding and painting/powdercoating/plating.
Check out this thread on the Hotrodders Forum:
http://www.hotrodders.com/t55679.html
The guy who started it (Randy Ferguson) is an artist in metal. He takes pride
in metal finishing without filler of any kind. Read the whole thread as it's
a bit old and some of the pictures were moved from one site to another. They
re-appear later in the thread. While you're at the Hotrodders.com site, check
out the Body & Exterior forum. http://www.hotrodders.com/forumdisplay.php?f=19
Look for the stickies and FAQs at the top of the message list. They also have
a fantastic knowledge base that can answer most of your questions without you
having to ask them.
Good luck on the '53, and don't forget to take lots of pictures while you're
working on it, and when you get it done!
Mark - '54 GMC 1-Ton Panel - "Moby Truck"
In a message dated 7/21/2005 10:35:17 AM Pacific Daylight Time,
owner-ole-trucks@autox.team.net writes:
From: "Paul A. Thomas" <bluewhale@jaxkneppers.com>
Subject: [oletrucks] Paint/POR question
I've read posts over the years extholing P.O.R. as a rust preventative
measure, however it seems there is a 'not quite right' feeling in the
posts about using this product. Is it because the painted surface
'feels' differently than standard primer? Is it easier to damage while
sanding for the final paint coats?
I'm curious because my '53 3600 has rust coming out all over the body.
The rust is coming from underneath. I've tried a few things over the
past 5 years working on a small section on the top of the cab to see
what might work, but even right angle wire brushing down to bare metal
then priming within 5 min, priming again and painting doesn't seem to
work completely. I did this test last about 2 years ago and areas of
the redone cab are starting to bleed rust through the paint again.
I don't wish to go to something like P.O.R. if it produces a soft
texture as I will need to sand when prepping for the 'final' paint coat.
Might there be a chemical I could wipe the bare metal with just prior to
applying the primer?
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