you want to sand that up abit with 36 grit or 40 i use a da so you do not over work the steel and make it to thin you want to sand it any were you are going to do alot of filling with body filler or epoxy the body and go over the epoxy primer with filler i do not like to do that much but can be done that way to you can get a stack on and have shrink marks in the finsh to many over lays of stuff less is better