Hello I am new but hey. I have a 1960 Ford F-100 and the body is in decent shape. It looks like it has been painted before. I went and wet sanded to just clean it up and smooth it up and then I put some black rattle can primer on it to just make it one color for now. I know I have to take the primer off but I was wondering if I could just scuff it up and but that epoxy primer on top of the old paint. I will be grinding some areas down to bare metal and was wondering if I use that phosphoric acid to prevent rust or to make the epoxy primer to stick. When I put the acid on do I have to clean it off? I also wanted to just make the primer the color. Instead of shooting a shiny paint. Do I just color the epoxy spray it one sand it smooth and I am done or what? thanks for all the help.