I have a new fender to put on my truck. It has been primed with who knows what. I was going to scuf it and prime it with epoxy primer to seal it and then paint the outside as normal. What about the inside of the fender? epoxy primer fine? or should I use undercoating, duplicolor brush on bedliner? Don't want it so rust anytime soon again!

 

A couple of good wet coats of epoxy primer would do it. On my '65 not only did the outside have the Holly Green color but so did the inside of the fender. Since that is how it came from the factory that is how I painted it last weekend. Two wet coats of epoxy and two wet coats of SS urethane on the inside.