I used to build street rods in another life yrs ago. The "enamel based" paints will go over "laquer based paints". But, NOT the other way around. When you try laquer over enamel you will get serious wrinkling and raising,like what CampGems ran into. On the new stuff,I think you'd have to test each different paint. The old paints(the stuff in the spray cans like Rustoleum) dry form the "outside-in" The new stuff dries chemically from the inside- out.