1 part epoxy primer and more primer..
^^^ Sure can. If you DA to clean metal, it will flash rust. If it does just take that off with whatever it takes, then get it in epoxy primer. Does not matter of large or small area. I hate rust and many times it cut out the rust, do my patches, epoxy prime those areas. DA ing the entire car takes some time. I tend to put if off.
I like getting urethane high build over the entire epoxy/car as soon as possible. Just me.