Quote Originally Posted by lcorrell
In their oppinion, the problem with the Kirker popping came from the fact that Kirker has no true base/clear system.
It's certainly true that the system you used is a single stage urethane with clear over the top. Kirker does have a "basecoat" system, although their basecoat consists of their acrylic enamel with an added basecoat stabilizer ("Lazerdry"). This Kirker basecoat sprays OK, but IME has poor coverage. The application of clear over the top of a single stage is not particularly unusual, nor restricted to only Kirker. People do this with other companies' single stage and clearcoats. Chemically it's pretty much identical to applying a couple of additional coats of single stage, or applying a couple of extra coats of clear on a basecoat job. Did they offer an explanation for the problem only occurring on the vertical panels?
Quote Originally Posted by lcorrell
They said if they were doing it, they would have let the ssu completely cure, scuff sand it, and then apply the clear.
I agree that this would be a perfectly good approach.
Quote Originally Posted by lcorrell
They also pointed out, similar to what Harry almost illuded to, that having airflow over a surface makes it dry faster - like blowing on a wet surface makes it dry faster. So, more airflow accross the paint would have made the paint skin over faster trapping even more solvents and making the problem worse!
No, that's incorrect. Hardened urethane paints cure via a chemical reaction involving isocyanate-driven polymer chain growth and crosslinking, not through evaporation. The reducing solvents are present primarily to allow the paint to be atomized and sprayed onto the surface. The chemical hardening reaction rate will be affected by the temperature, but not by the airflow. The airflow will significantly change the rate of evaporation of the reducers/solvents but will not significantly change the rate of hardening of the paint. More airflow will allow the evaporative removal of the solvents before the chemical hardening reaction gets very far along. Low airflow allows the sovents to remain in the paint while the chemical hardening reaction proceeds, and will lead to solvent pop.
Quote Originally Posted by lcorrell
Maybe I should have shut off the fan after I was done spraying instead of leaving it running while the paint cured?
That would have made the problem worse, not better. As Len pointed out, professional paint booths move a lot of air, much more than anybody's home garage setup.

Harry Phinney