You can see when the base coat flashes because it goes from semi-glossy to flat once it has flashed. Omni MBC calls for 2-4 coats. Some colors like bright red might require more coats because it is more transparent than something like black. Also unless you are in a cold place, I wouldn't recommend a fast reducer. a slow is what you need in 70+ weather. My flash times in 80F, high humidity weather are about 8-12 mins. sometimes faster.
I see some of you spraying 3 coats of clear. Omni AU clear calls for 2. no more no less. Too heavy of a coat will sag and too little will make it bumpy because there's not enough material on the surface to join the droplets. I usually wait about 15 mins or so before applying the second coat seeing how you can't really tell by looking. you can touch it if you want to see if it's tacky, but your fingerprint will be in that clear permanently.
I use a satajet 1.3 for the base and 1.5 for the clear. I also seem to be able to get away with spraying primer with the 1.5 tip as well, but I would recommend 1.6-1.8.
Unless you get runs, I wouldn't sand after the primer (320-600grit). If you do get runs, depending on how transparent the color, you might have to go all the way back to the primer and start over. I've tried color sanding with 1000grit and after clearing, you really can't tell the difference plus like others mentioned, if you are using a metalic or pearl coat, you can't sand it prior to clearing it.
If you are not familiar with spray painting try it out on a test hood or panel if you have any spares or get one at a junk yard and section it off for more than 1 attempt. btw, be careful when applying clear with tape above the area you are clearing because the clear runs off the tape easy. Try and just mask it off with paper stretched at the ends with tape. that's if you are painting vertically though. I'm not sure what would happen if you had the part flat on the ground. (wow I did a google search and found this thread and didn't realize how old it was. but I hope it still helps someone out there)
Last edited by MetalDrgn; 10-15-2007 at 12:06 AM.