Body Work Expertise Needed

Ok I'll try and help you, first of all you cannot put any kind of body filler on a self-etching primer, DON'T DO IT, do the bodywork on the bare metal if at all possible, if the car is sanded to bare metal, it is the best first primer you can use, it is very thin and you will see thru it in most cases, make sure your metal is clean, it usaully mixes 1 to 1 with hardner, if the hardner is not in a plastic jug it's not self-etching primer, the hardner is phosporic acid and bites in and becomes part of the metal, hence the plastic jug, it's the best corrosion protection you can get, then you can go to a catalized primer filler usually called 2K primer or I suppose an epoxy primer would work as well I prefer 2K primer filler (3 coats) uaually because it fills so well and this where the sanding & blocking begins use 220 grit on a long sanding block, any small dents or imperfections you find after blocking can be filled after blocking with a polyester filler, these fillers sand very easily but normally aren't used for heavy filling, once you've got all the blocking done and the imperfections done, prime the vehicle again, and block it again, with 320 grit dry or maybe 400 wet or dry paper, using it on a block with water, at this point the body shpuld look pretty good and be very smooth, with today's base/clears I will usually block the car one more time wet with 500 or 600 grit, then it's ready for the topcoat, I don't normally seal them at this point because I've sanded it so smooth and a catalized primer doesn't really need a sealer, anyway that's how I do it and it comes from many years of experience as well as being a factory rep and instructor for a paint comany for many years, hope this helps