Fergus Kyle wrote:
> I appreciate your advice in this topic, but am having
trouble
> with sentence structure..... may I infer that the two methods of
adhesion in
> the products under consideration are (a) Tooth adhesion and (b)
Chemical
> adhesion?
All I meant was there will always be tooth adhesion, but two-part
epoxy primers are generally impervious to paint solvents. You can
test anything with the thinner to be used in the primer or topocoat,
if applied directly. How you can test adhesion of anything to a
waterborne coating like Smooth Prime, I dunno; is a test shoot that
lasts a year OK?
I did a sand-and-paint down to a solvent 2-part epoxy primer that was
only a couple years old, and then Imron topcoat. Still good after 19
years in the sun. But another time I used the same primer and shot
another poly, but the next day. Now the primer mfr said if you do
that, abrade it with Kraft paper. Huh? Well, I figured do what they
say, so I bought actual Kraft paper and sort of abraded it, I guess.
The topcoat mfr doesn't say it's OK to use this primer either, but
that poly is still good today.
I didn't find out until recently that this primer I still use on metal
stuff (re adhesion) needs days of cure before you can wet sand it,
though it's no longer tacky overnight. If you wet-sand it too soon,
it balls up in the paper; it may be the phenomenon where epoxy can
draw in water by osmosis not absorption. Dry Kraft paper must break
the surface tension if still soft enough, which is the minimum
required for topcoating.
I've also never had trouble with any poly or acrylic, over common
spray-can primer on small plastic fairings. No sense to me in mixing
gun-clogging epoxy for small parts which don't need the advantages of
that paint.
> I plan on leaving the spray work to a professional
(commercial)
> painter .......and how do I voice my question to the provider?
I recall a sign posted in an auto repair shop, "Watching -
Free....Questions - $10....Suggestions - Forbidden."
Reg,
Fred F.
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