To get back to the melty paint, Bossy, I noticed your comment about pressure. Automotive paints are usually sprayed at pressures airbrush compressors cannot reach. I'd say this might explain the bumpy finish, it would also explain the "heat" of the paint.
Modern HVLP guns operate with an input pressure of 30PSI, Old School Siphon guns can be as high as 60PSI. plus they have a fan pattern aircap to further atomise those droplets.
I used to spray fast drying thin Primer coats at 60PSI, with a cheap gun, then after nibbing the Primer, I'd spray the Gloss as one mist one medium, wait for flash and one Heavy coat with slow thinner all at 45 PSI with the Devilbiss Siphon Gun.
At that pressure, everything but the heavy coat was dry in around the time it took to finish the length of the vehicle and come back for the next overlapping pass. as such, the solvent doesn't hang around long, until that last heavy coat, by which time it's got 5-6 coats of dry paint under it, at least 3 of which are cured.
9. July, 21:27