Time between sanding and painting

General Discussion. Make yourself at home...read, ask and answer!

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PostPosted: Tue Feb 11, 2020 10:46 am
So you are planning to just sand the original paint and then spray your SS correct?
If so what condition is your original paint in? Is the clear faded or peeling?
Are you planning to sand down to the primer or just scuff up the surface for a repaint?
Will you be applying a sealer?
1968 Coronet R/T

ACTS 16:31

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PostPosted: Tue Feb 11, 2020 7:39 pm
NightTrain wrote:Back in the "old days", 320 grit was the standard for final sanding for
acrylic enamel. For today's formulations, I too would go with 600 grit
just to be on the safe side. Especially with black. Definitely use a
hardener with the acrylic enamel, for higher gloss, better durability,
and a shorter recoat window in case repairs are needed.

I'm curious as to why you chose A/E instead of urethane single stage?
Nothing wrong with it, it's just an older technology than the newer
urethanes. Sometimes 50's and 60's cars look better with the same era
A/Es on them...

:goodpost: your right i remember the old Centari A/E specified 320
Jay D.
they say my name is Jay

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PostPosted: Wed Feb 12, 2020 4:13 am
My paint system is Centari and I love the concept of common tinters with just a binder change to make different paints, including the L400 acrylic enamel which I use regularly.

The idea of 320 grit as a base finish for AE went out with panel beaters who would only file finish. Might have been straight, but who wants 40 grit grooves in their bonnet?

These days the correct preparation is P500 dry on a DA or P800-P1000 wet. Best results will be on a 1K primer where the topcoat will actually melt in to the primer. I sand P180-P240 dry before the primer, especially over a hard, cured substrate.

For 380S (the best 1K clear in the world) correct preparation for a fully cured substrate is P1200. Obviously solids only, metallics/pearls should be WOW, not sanded.

Hardening AE is optional, but 5% Acrylic Urethane hardener will work well.

L400 acrylic enamel can be applied absolutely dead flat, so no peel or urethane wave. In my opinion gloss levels, after wet sanding and buffing, can surpass those on urethane paints. If the substrate is acrylic then you will never get clearcoat or topcoat delamination although, like all acrylics, after many years in the sun, the paint will dry and start to crack. Long after a urethane has delaminated though.

Using the best quality, slow thinner, is essential. I only use PPG Dulon AAA with acrylic topcoats.

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