Epoxy primer

Epoxy Primer is a Primer Sealer.

When doing body work there is a product called Primer Surfacer that sands easy and is used for leveling and filling imperfections and sand scratches over the bondo work.

Primer surfacer works good if you are going to get to the car right away and get it painted right away so it is all sealed up.

People use the Epoxy primer because it is tough and is a good base to put down after a car has been stripped. It seals out moisture penetration too as lots of these cars can sit around for years before they get finished, so it's good to have something to seal the bare metal and keep it from drawing moisture and rusting while you work on it.