Originally Posted by adic27
Ospho is the same as or similar to rust converter? If not would you recommend it over the spray I mentioned?
Rust-Oleum rust reformer is a little different than Ospho. The Rust-O product is the kind of goop that has an acid for dissolving the rust (I think it's tannic acid but I'm not sure) and converting it to ferrous whatever, and also some added polymers that form a sort of plastic-y protective layer. Ospho is just phosphoric acid, which dissolves the rust and converts it to ferrous phosphate. It also leaves a sort of protective coat but not one as long-lasting as the rusto.
The rust reformer is probably better overall and it's definitely better anywhere you won't be bothering to paint afterwards. Ospho is good and I've killed a large amount of rust with it but there's no reason to ditch what you have.