Rant: I tried warming panels with a heat gun instead of the booth and one quarter panel humbled me
About six months back I was rushing a respray on a 2011 Civic and figured I would skip preheating the booth and just run a heat gun along the quarter panel to speed up the flash time. I kept the nozzle maybe four inches off the metal and moved it in slow passes, and the first coat laid down glass smooth, which had me feeling pretty smart. Then the second coat came out with solvent pop across a patch the size of a dinner plate, and I had to sand the whole panel back down to bare steel and start over on a Friday afternoon. What I figured out is that a heat gun heats the surface way faster than the metal underneath, so the top skin dries and traps the solvent still trying to get out. Anyone here got a trick for warming a panel evenly without dragging out the booth heater, or do I just eat the extra 20 minutes and do it right?
Man, I felt this one in my bones! I read a thing from an old painter on a body shop forum who said the exact same thing you figured out, that heat guns trick you because the top feels warm but the steel underneath is still cold. He said the trick is to keep the gun moving way farther back, like a foot or so, and just wave it around the whole panel in big circles instead of slow passes up close. That way you warm the metal slow and even instead of cooking the skin. Some guys use an infrared lamp on a stand for this and just let it sit there, which sounds easier than holding a gun for ten minutes. But honestly, 20 extra minutes in the booth beats sanding a quarter panel back to bare steel on a Friday, no contest.