Walt:
I'd suggest picking up a good auto body book for some professional
advice. There are also a lot of really good web sites.
You are doing a couple of things wrong. The rubbing alcohol
contains water, which is not the best thing to be putting on the exposed new
surface. There is a product called Prepsol, which is designed for cleaning
the painted surface first before you push the silicones and tars into the
metal with the sandpaper.
The self etch primer, is a reasonable way to go for spot repairs,
but not as good as a properly etched surface. The main problem is that a
primer is porous. It is designed to absorb the top coat of paint for full
bonding. Primer paint are not a barrier for water or oxidation. The primer
must be covered by some kind of barrier coating.
One step products such as "Extend" by Permatex contain a conversion
product, which chemically converts the rust, and a barrier material, in this
case Latex (I believe). POR is another product that converts, then coats
with a moisture setting barrier coat.
Check out some of the available material. You want to convert the
rust, then protect the damaged panel from moisture and oxidation with a
secure barrier coating.
Kelvin.
> I have been slooowwwwlllly fixing the body on the 77 and cannot seem
> to stop the rust. Sand down to bare metal, clean well with alcohol
> (rubbing alcohol, not drinking), and then primer with what's called
> self-etching primer. Supposed to bond to the bare metal. In all
> cases, rust is coming through the primer after less than 1 month.
> Is there some type of primer that will stop the rust? Or is there
> some other method I should use when removing dents/scratches?
> TIA
>
> Walt Goddard
> waltcpa@sierra.net
>
>
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