painting over sealer
I have been sanding 2 layers of paint and sealer off of my project car. Once I get down to original paint, I use it as a guide to find the irregularities in the metal, dings small dents, scrapes. I then work on fixing those problems along with any rust.
Rusted metal is replaced. Bondo used to smooth out. Any bare metal is primed with etch primer except where bondo is needed.
I then spray sealer on after all body work is done. The sealer has set past it's spray window, I plan to spray a sanding filler primer on and do a final block and wet sand on the whole car, once I get to that point.
My question is, since the sealer has set for so long, what would be the best procedure to insure a good bond? I don't think a scuffing would be enough, but I dont want to sand the sealer off. Is there a chemical method to let the next coat get a bite on the sealer? Can adhesion promoter be used on primer instead of plastic?