You can buy a paint called X-O Rust at True Value hardware. It is water based enamel, goes on in a rather thick coat with a brush, and can be painted over rusted metal (as long as dust has been removed). Decent stuff, doesn't cost a lot and really easy to apply & clean up brushes and your hands. Resistant to salt, also. If you apply a second coat, I think you have to wait 24 hours. POR...very thin, get it on your hands and wear it for weeks. There are better products which aren't overmarketed and overpriced.
