I'm thinking about using something like Duraglass for most of the filling and skim it with regular body filler to finish. Or would it be better to smooth the finish coat with something like "Icing"?
Question is, do I apply the filler straight to the metal after roughing it with an 80 grit disc as we use to do it or prime it with epoxy primer and then the filler as many say to do now??

John