In a message dated 11/25/01 8:38:47 PM Eastern Daylight Time, TATERRY@aol.com
writes:
> someone said that POR15 stuck to rusty metal better than clean metal
> and I think they said it had some phosphoric acid in it....??
> I was under the impression that POR15 was a moisture cure urethane
> that kept oxygen off the metal and that is its magic....is this not true?
> Terry in Oakland
Terry,
POR-15 has a very good web-site at www.por15.com. I think you may be right,
there is no mention of the product reacting with the rust. They do claim it
chemically bonds to the rust, but there is no mention of how. Seems like
just a really tough paint-like (polymeric isocyanate derivative) product.
Although POR-15 it works on rusty metal there's no reason you can't use it on
new (i.e., non-rusted) sheet metal. The key seems to be the use of their
pre-primer product which etches the metal and leaves a zinc coating.
>From their site: "Application of POR-15B. to new metal: For proper adhesion to
aluminum, galvanized metal, and smooth steel surfaces, prep with POR-15B.
METAL-READYb" Rust Remover/PrePrimer. Keep surface wet for 15 minutes, then
rinse off with water and dry thoroughly. This process will leave a zinc
phosphate coating on the metal and insure perfect adhesion."
Anyway, my Saab mechanic uses POR-15 after welding frame repairs and swears
by it. Just make sure you use the pre-primer.
Donny V
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