Main goal for this type of job is to get the surface very clean and a good bond for the paint. Don't want to cause problems later for the paint shop when you get the good job done. Wet sand the entire surface with 320 wet or dry until it is totally sanded. Then go over the surface with wax/grease remover (lacquer thinner works too but will dissolve paint if you linger so rub it down quickly). Clean out rust to bright metal, dont leave ANY rust or it will bubble the paint eventually, guaranteed. Prime all bare areas with etching primer before putting on a coat of "suede". A quart of etching primer will go a very long way. Only need a light coat as a base for filler primer. DON'T strip off good solid original paint thinking bare metal is the best starting point. Bare metal is much harder to paint than a good, solid, well sanded original paint.
As far as the bondo is concerned, if it is well bonded to the surface and not too thick (nothing over 1/16" thick) then just sand it and finish it like it was regular paint. You can primo out the body work first or leave it rustic, doesn't matter.
As far as the bondo is concerned, if it is well bonded to the surface and not too thick (nothing over 1/16" thick) then just sand it and finish it like it was regular paint. You can primo out the body work first or leave it rustic, doesn't matter.
