You are right 51, the window is all about adhesion. The chemical adhesion of the
epoxy primers is non-existent after the recoat window. Then it is all
mechanical.
Old (non-compliant) epoxy primers had lead (per the paint company owner)
that allowed the window to be almost unlimited. But they can't use lead anymore.
Urethane primer doesn't have that limitation.
So I am applying an epoxy sealer coat over the old sanded epoxy (doesn't have to
be thick) for adhesion, then a thin urethane sealer coat to allow for 600
sanding
and extend the window. As I explained, the paint company claims you don't
need to sand the epoxy primer sealer coat to hide the 180 sanding marks but
I tried and not very happy.
Regarding "Cut and Buff" as it is called here, it is very common in car circles.
It is almost a must because the paints do spray very orange peely these days.
If you don't want that look then you need to do it and most people just plan
for that. The good news is that the paints are designed for that and the more
expensive ones like the one I am using remain softer to allow better buffing.
Modern sanding and buffing materials are also much better.
But talking to the paint company owner yesterday he told me people cut and buff
if it is a car. He has not seem many airplane people like us doing it. Maybe
if you want an award winning plane. I wouldn't mind having an orange peel free
finish but will probably just live with it. I tried everything and learned that
heavy orange peel is a fact of these modern paints unless you are a robot.
I have heard than some cheaper paints may flow better but then quality suffers.
I will ask the owner about what you mentioned regarding micro pores or
durability.
Good point, lets confirm it.
Chris
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