Autobody Question

[Rivet]

I've layed down my epoxy and high-build surfacer. While block sanding, in a few small spots I have gone down to the aluminum (rivets, some edges and curves). My question is, can I apply an etch primer from a spray can to hit those spots? I really don't want to mix up more epoxy primer, but I can if I have to.

 

[jafir]

I'd use the same stuff you used before. No personal experience here, but I saw on a buddy's car where when they laid down the color, it bubbled up in some spots where a repair panel was welded in, and the panel was primed with something different than the rest of the car, that didn't like the paint they were using. I'd hate for there to be some incompatibility that you don't find out until it's too late.