I had similar experience to GMDad. Went to a lot of trouble cleaning up a subframe and rear end and painted it with POR-15. First time in a quarter car wash, it all came off in sheets. When I complained to the distributor I was told I should have used their primer over clean metal - the paint is designed to work as named - "Paint Over Rust". It bonds with rust, can't get a bite on clean shiny metal. They sent me two free cans and one of primer.
