I have a 69 Mustang coupe that I'm working on.It had a vinyl top on it.Took that off and found plenty-o-rust.Also discovered that I can't buy repro coupe skins....ugh!If I sandblasted both sides of the skin and applied POR-15 on both sides would it hold?I know this is probably a stupid question but thought about trying it and letting the car sit outside to see if it would rust again.Otherwise I will just have to cut and patch.