I don't do auto paint but from what I've read it's hours.. The colors seem to dry pretty fast and won't even look good till the top coat is on.

Boy, I was guilty of what I see allot on the forums.. Not reading the question throughly... Ya over dope I would wait several days..

Thanks guys, that's what I needed to know.

one very important thing people tend to forget with air dry products,, well all products actually is the rule of 15,, if its 15 degrees cooler it takes twice as long to dry, if its 15 % higher humidty it takes twice as long to dry. To make across the board statements about dry times without taking into account the number of coats of material, the temp , the solvents, and the humidity is a bad idea!!!
Ok so to anwer the question, first statemtent,, ( i have to say it) urethane over clear isnt a great idea,, but,, if your going to do it,, then, I would test my laquer for being dry enough by lightly scuffing a spot of solid color , the last color sprayed,, you shouldnt really smell any solvents after you lightly scuff it. think scratch and sniff,, In other words, take some 600 grit paper and smell a small spot, then scuff it wet, dry it and sniff again, there should not be an appreciable difference in the aroma.

While I would never think of disagreeing with Mark  (     ), I would shoot a highly thinned coat of clear over the colors. It tends to lock things down and keeps unpleasant things for happening. I've done this without problem (now, if I could just keep bats out of my shop, I won't have 3 coats of catalyzed polyurethane on planes and they won't weigh a ton).

I admit my data base is small.

I have built 9 stunt planes using dope then Dupont Nason clear top coat.

My 3 day wait burnt me. Bubbles started once the plane sat in the hot summer months.

The planes I waited to gas off, no bubbles.

If you live in a desert, start clearing. Otherwise wait a bit.

You can also use the rule of 15 (although I aalways heard 10) to your advantage.

If you can raise temperature and/or lower humidity (within reason), outgassing will happen faster.