LOCTITE® SF 7500 is a blue/blue-green, solvent-free, non-toxic, aqueous liquid which dries at room temperature. It converts rust into a black, stable matt black complex and forms a protective coating on exposed iron and steel surfaces and also creates a suitable primer for most types of paints. Suitable for metal pipes, fittings, storage tanks, railings, conveyors, overhead cranes, booms, agricultural equipment and so on.