use it all the time and have had no problems, just let it dry(I go overnite but I'm in no rush) then sand it(wet recommended)with 600 then 800 and for light metallic colors go to 1000. I paint for a living
In fact I use automotive catalyzed urethane clear coat on all my plastic models, no matter what type of color paint I use! I also spray the chrome trees with the clear so the chrome doesn't fade or rub off. This stuff is safe as a kitten. Only trouble is, it is so tuff that none of the tricks used to strip plastic model cars (brake fluid, EasyOff oven cleaner, etc.) will touch it! better be happy with the paint job B4 clearcoating it.