POR-15 as a powercoat substitute?? Never heard of that. It's used extensively for restoration projects where rust is a problem.. particularly on frames, floorboards and internal body panels. Although the web site doesn't say it, "POR" is supposed to be an acronym for "Paint Over Rust", and it will stop rust dead in it's tracks and permanently. It's not cheap, but I know a LOT of people who swear by it.

POR-15 web site

Cheers,
Brad

To be old and wise, you must first be young and stupid.