Join Date: Nov 2006
Location: Oklahoma City, OK
Where are you buying paint? Do you have access to Nason? I used Nason 2k sandable primer (made by DuPont) on my '70 and 5 years later I am still rust free. Purchased it at Oreilly Auto Parts. It is super resistant to fuel and oil and has taken a ton of trail abuse. There are spots where my paint has been scratched, but the primer held up. I even stuffed my rear tire into the fender one time and creased the rear quarter at a 90deg angle and the primer bent around the crease without cracking. Sands super easy. VERY reasonbly priced, too.
Just my $.02, but after messing around with painting a couple vehicles now, I have adopted a process where fillers/glaze never touch bare metal. Once I have made my metal repair, I sand everything down to 300 grit, shoot a coat of Nason 2k primer, THEN apply my fillers. My theory is that it adds a layer between the filler (porous, traps H20) and the metal. It is working out well on the projects I've done in this manner. YMMV.