*Guess I should have read the post first*
My reply is really for automotive paint. I've clear-coated a couple tanks with good results
(2 yrs still good - I do store inside etc.)
I've used a urethatne clear w/ hardener... the trick is to put down several 3-4-5 mist coats -
just spray it to where it just kinda "glistens" don't lay it on wet. Let it flash in between coats.
Let the last misting coat flash a few extra minutes before putting a final coats on it. The first
final coat- not so thick, the second you can lay on wet.
I've also cleared directly on top of decals as well. Those are kinda touchy though. If they are true decals, the mist coats are a must. If they are vinyl decals, it kinda depends on the type of adhesive that is on the back... some are water-based adhesives and some are solvent/acrylic based.
I've found that just putting a bunch of mist coats keeps the solvents from attacking the adhesive as bad as they would if you just layed it on wet.
That being said.... I sure would like to see the clear powder coat after a few years in the sun.
That seems like it would be the surefire way to go. Only problem in coating over decals.
Are your decals original, or are they after market vinyl decals?