Septone Rust Prime is a water based chemical that converts rust to an inert black compound and simultaneously primes and seals the metal surface so that it is ready for subsequent priming and topcoating. Rust Prime may be used on rusted galvanised roofs or surfaces, ornamental ironwork, fencing, structural steel, gutters, sheds, rusted nuts and bolts and hand tools. It can also be used in a number of marine applications. Rust Prime will provide temporary protection against rust, but should not be considered as a corrosion resistant coating. Primer coats and top coats should be applied as soon as possible after the surface has been treated with Rust Prime (and within 4 weeks) .