In a message dated 96-05-16 06:22:07 EDT, you write:
>There are basically three classes of product
>Conversion coatings.
> These are intended to convert existing rust to a stable coating
> that prevents further water from reaching the raw metal. Ex. Extend
<snip>
>I understand also that DURO and Rustoleum sell products called Extend.
>I don't know I am suprized that with all these product with the same
>name there is not more controversy over the product name
>I don't have any information as to longevity, but I have heard that these
>are good (not great products).
>
Well, there's another way of using conversion coatings, and that's by using
the more traditional "body shop-type" materials like DuPont Metal Conditioner
and Conversion Coating (various numbers depending upon the metal to be
treated). Basicaly, just referring to steel now, you use a phosphoric acid
material and mechanical means (Scotch-Brite, etc.) to clean away any existing
rust (even "clean" steel has some microscopic rust) and then apply the (again
primarily phosphoric acid) conversion coating material to make a better iron
phosphate coating on the surface.
The difference with the Duro/Loctite (owned by same company) "Extend" and
Rust Oleum's "Rust Reformer" is that these materials combine cleaning and
conversion coating materials together, and put the reagents into a vehicle (a
shellac-type compound for Extend, and a latex-type material for Rust
Reformer), so you're putting on a protective finish along with the surface
treatment.
I've used all of these, and have been generally impressed. I put Rust
Reformer on some very rusty outdoor furniture about 3 years ago, and haven't
painted it yet. I just looked at it through the window, and while I may give
it another coat before painting, it's pretty much the same as when I coated
it. The gloss disappeared, but there's no new rusting evident. Protected by
paint, I'm sure it'd be just fine.
>Oils (Waxoyl)
>Waxoyl is an old stanby product, I believe Moss still sells it.
>From what's been written here a few months ago, Waxoyl is primarily a sealer,
and basically inhibits by feeping oxygen and moisture off of the steel rather
than actually chemically converting the surface like the above materials.
You wouldn't want to paint over it. It sounds great as a hidden-area
rustproofer -- I'm planning to get some and try it now that the weather is
improving here.
Good Luck
-Karl
|