Well, for one thing, Laquer on cars is ACRYLIC laquer,, it is a different base carrier than Butyrate Dope. Both laquers, but completely different chemistry. ( One of the reasons I harp about using the thinner designed for your paint, not some other stuff) The other thing is, consider the guy behind the counter, if he sees the delamination 5 or 10% of the time, he is NOT going to want to reccomend it because of his reputation. The biggest factor i think is that our creations dont spend 24/7 in the sun AND probably more important, on a car the solvents have nowhere to go except into the urethane clear. Whereas on our planes, the solvents can go AWAY from the urethane through the covering and wood to escape. Keep in mind, laquer NEVER EVER dries completely, it is always out gassing solvents so when you top coat it with Urethane those solvents have to escape somewhere. On a car, they cant go Down, theres metal there, so they come out of the laquer and break down the mechanical bonce between the laquer and clear causing delamination
Hope this helps...
Still , do I think its a good idea,, in the purest sense, simple answer, NOPE. will it work,, most times yes assuming you allow the laquer enough time to truly dry

Clint,

The first plane I used Dupont Nason 2 part auto clear on was in 2003. It still looks good. (No separation)

Good enough to hang in my local Hobby Shop today.

The only plane I had any problems with was because I only gave it 3 days to gas off before clearing. (Bodak dope under clear)

thanks CLint, and good luck with the clear. One thing you find in auto repair is a sealer coat on EVERYTHING. makes it one color under your color coats. Next time spray a light cover coat of white before you spray color. Or even a light grey helps.

Still , do I think its a good idea,, in the purest sense, simple answer, NOPE. will it work,, most times yes assuming you allow the laquer enough time to truly dry

So generally speaking, whats is "enought" time for a dope color coat to dry before spraying an auto clear coat.

When my grandfather built one of his Mustangs, he used a different type of clear on it, I think it may have been a polyurethane clear coat over Brodak dope.  The paint didn't adher to it at all.  Guerry Buyers asked him if he spilt coffee on it, because it looked exactly like a coffee stain.  Now he is refinishing it but the way it looks now, it looks like he is repairing it.

What is the difference between polyurethane and urethane?