Technically rust is an inorganic oxidation process and it needs both moisture, oxygen, and steel of course to occur. [Organic chemistry is the study of compounds that contain mostly carbon and hydrogen. Iron oxide (rust) only contains iron and oxygen and is therefore discribed as an inorganic compound]. For a long term fix you need to either physically remove the rust and then seal the metal with primer/paint, convert the rust (after first removing all loose rust and dirt) from iron oxide to zinc phosphate (Eastwoods - Oxisolve) and then prime and paint, or you can use a rust encapsulation product (Eastwoods - Rust Encapsulator or POR-15). If you could effectively seal the metal from moisture and oxygen you could stop the rust, but the problem is that regular primer and paint needs to make a mechanical bond to the surface to make a good seal. A rusty surface is not a stable surface in which to make this mechanical bond, it would be like achoring a new deck railing into rotten wood.
