Scott, there may be one other issue with using a hardener with some paint; bonding of the various coats. Now, you didn't use a urethane, but you did use the same type hardener, and one of the things all the manufacturers (and how-to articles I've seen) stress is you have to apply each coat of paint before the previous coat fully cures. All the numbers I've seen is a 16 hour max, less is better, and preferably within 60 minutes (15 minutes is enough 'drying time' for applying another coat usually). If you wait too long, the paint cures too much and any coats applied don't bond to the lower coats. The hardeners require a chemical bond, and once the paint cures beyond a certain point, you won't get that bond. At that point, you're supposed to re-sand with some fairly coarse paper (220, 320 at the finest) to give a 'toothed' surface (for a mechanical bond) for the paint to stick to and shoot another coat of primer to apply the color coat to (without sanding the primer).
Basically, you apply all the paint, then sand it. It's OK to sand intermediate coats, but only if you do it within that 'cure window' before putting another coat on. 'They' say this is a leading cause of clear-coat failure, applying the base coat then waiting too long before putting the clear on, but point out that the same problems can appear in the base coat or single-stage paint if that 'bond' isn't made. This can be a PITA, as you have to do all the painting to say inside that 'window' so once you start, you have to see it through until all the paint is on. No stopping in the middle....
The other thing all the 'pro how-tos' mention is staying with a single manufacturer for your paint, at least in the color coat/top coat paint. Mixing brands among your paint, reducers, and hardeners isn't recommended.
Basically, you apply all the paint, then sand it. It's OK to sand intermediate coats, but only if you do it within that 'cure window' before putting another coat on. 'They' say this is a leading cause of clear-coat failure, applying the base coat then waiting too long before putting the clear on, but point out that the same problems can appear in the base coat or single-stage paint if that 'bond' isn't made. This can be a PITA, as you have to do all the painting to say inside that 'window' so once you start, you have to see it through until all the paint is on. No stopping in the middle....
The other thing all the 'pro how-tos' mention is staying with a single manufacturer for your paint, at least in the color coat/top coat paint. Mixing brands among your paint, reducers, and hardeners isn't recommended.
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