I have been seeing in different build posts about guys using POR-15 on their cars. That stuff is supposed to be used with a certain amount of rust to make it work properly. If you clean the metal shiney, it won't stick. Ask me how I know.:violent1: The surface has to be somewhat rough and have some rust to work. I have tried 2-3 times to clean the metal, then use por-15 to find out a few years later it chips right off. Ever since those cars, I just use a rust convertor then paint. Cheaper.