[MP&C]

80 grit DA, metal should be free of rust, oils, and any other contaminants. Preclean with Wax and Grease remover, not lacquer thinner or other reducers. W&G remover is a slow to evaporate solvent that floats impurities to the surface where they can be wiped off before the solvent dries. Thinners flash off too quickly and can leave impurities that lead to fish eye. I would recommend SPI epoxy in black or similar for your sealing substrate. This sets up in a semi-gloss finish and turns a charcoal grey look when sanded, so essentially provides it's own guide coat, no need for the dry stuff.