Epoxy vs Urethane Primer
I've just discovered this bulletin board, and although I am not a hot-rodder, I hope you won?t mind my asking some questions.
I am restoring a seriously rust-damaged MG Midget. The running gear and all components have been removed from the chassis. I've replaced all of the damaged metal with new steel and I am getting ready to apply primer. New metal is either galvannealed steel, plain steel sheet or black primed replacement panels. Remaining original metal has been chemically stripped to bare. Everything has been sandblasted (including the replacement panels) and then chemically etched with Eastwood's Oxysolve which leaves a dull-gray zinc phosphate coating on the steel. (This description applies to all interior and underside surfaces. Exterior surfaces have not as yet been touched and are either original lacquer or black primer, which will be removed prior to refinishing.)
I have nearly zero automotive refinishing experience so I asked my paint supplier for advice. I have read in several places that epoxy primer should be applied over bare steel. The paint supplier said that is no longer true and that I would be better off using a urethane etching primer on bare metal, followed by a 2K high build primer. He said that the new urethanes are better than the epoxy primers. I ended up leaving with Western Automotive Refinisher's Select RS1000 Etching Filler and RS3702 2K HS Primer.
I have the engine compartment primed with the RS1000. It applied easily and sands very nicely. I am moving on to the interior of the tub and underside of the chassis. Checking this bulletin board I see that it has been recommended in several places to start with epoxy and then 2K urethane primer.
Any comment on starting with a metal etching urethane primer such as the RS1000? This has been way too much work to mess up the paint at this stage of the game.