Walt, Kelvin is dead on. The alcohol is causing problems. Even if it were
absolute alcohol the OH on the end promotes oxidation. I use a product
called oxisolv that leaves zinc phosphate on the metal.
First I sand and make sure all the rust is gone. I then clean the part with
a highly volatile solvent that will not leave a film. Then I heat the part
with a blow dryer to make sure all traces of solvent are gone and
immediately apply oxisolve. I let the part dry until a light gray film
appears. Ready for the primer and paint. Enrique
At 12:11 p.m. 17/08/2000 -0700, Dodd, Kelvin wrote:
> 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.
> > 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
> > firstname.lastname@example.org
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