Fluid Film Black Corrosion and Rust-Proof Undercoating in a 5-Gallon Pail is specifically designed for undercoating purposes. The wet coating will soak into the pores of the metal and leave behind a slick, non-drying film that protects from salt, brine, and atmospheric corrosion. Even with existing rust, Fluid Film Black can soak into the surface and stop it from progressing. Solvent free, no silicones or teflons. Fluid Film is formulated from specially processed wool-wax, highly refined petroleum oils, and selected agents to provide corrosion control, penetration, metal wetting, and water displacement. These long-lasting products contain no solvents, will not dry out, and will penetrate to the base of all metals, providing corrosion protection from both natural and industrial atmospheres. Heavily corroded and/or frozen parts such as nuts, bolts, shafts, etc. that would normally be damaged during maintenance, can be salvaged by applying Fluid Film. Protects from salt, brine, & atmospheric corrosion Can soak into the surface & stop existing rust from progressing Solvent free with no silicones or teflons | Fluid Film Black 5-Gallon Corrosion and Rust-Proof Undercoating