POR15 is a bit rubbish tbh. I read great things about it and tried it on some motorcycle parts, but not only is it ludicrously expensive, it goes off in the tin before you can use it all. To top that off, by the time it had dried, there were little bubbles of rust on the surface of it! Its supposed to encapsulate the rust and use any moisture in it to cure, but it seemed to do the exact opposite.
Rustoleum is much easier to use, cheaper, and stays liquid in the tin. I painted all the steel work in my workshop with it and 5 years later its all still perfect. That's American too though
