ORIGINAL: mach1-RCU
(I probably would not use it to refinish a Porsche, though)
I have used SEM Self-Etching Primer on both aluminum....full scale leading edge touchup on aluminum......and on steel auto touchups.......leading edges were top-coated with Imron and auto top coated with PPG B/C.......I also did a re-spray of aluminum rocker covers with SEM on an aircraft engine prior to topcoating with a high temp epoxy......
No chipping or incompatibility noted......dries to touch in 15 minutes....sand in an hour.....beats a primer gun......
I am using some of the standard primer described in this thread for some touchup on my KingCat with PPG Concept being the topcover.......
Tom