[72HuggerK20]

Make sure your viscosity is right. Follow all mixing directions to the letter, except for reducer. That varies depending on your gun setup, temperature, humidity, etc. I usually look for it to take 1-1.5 seconds for the stream of paint running off your stirring stick to turn to droplets when mixing primer. Maybe try switching products brands.

I'd say not to go to lacquer. To prove my point, go get some lacquer, spray it on one junk panel, then spray urethane on another panel. Then go get some of the reducer you'll be using in your paint, wet a rag down with it, and wipe it over your primed panels. I'll bet the lacquer wipes right off, and the urethane will stay untouched.

Also, explain your sanding process. Urethane primers are meant to be sanded with fairly coarse sandpaper (start with 320), then stepped up to about 600-800 grit, then sealed. They are porous and will suck up basecoat pretty badly if not sealed first.