Cavity Wax Provides Rust Protection in Hard-to-Reach Areas

Cavity wax is an excellent solution for providing rust protection in hard-to-reach areas. Rust develops when steel or iron is exposed to moisture and oxygen. To avoid rust it is necessary to seal the metal from these elements. While many areas of a car or truck can be easily reached to apply a rustproof paint or coating, other places are often difficult to reach, leaving the metal bare and exposed. Examples of these areas are inside frame rails, rocker panels, fenders, doors, tailgates, windshield cowls, and posts. Cavity wax can be used to provide a barrier against salt, dirt, and moisture in these areas as well as seal the welds and seams that rustproof paint or coating can't reach.

What Is Cavity Wax?

Cavity wax, also called rustproof wax, is a solvent-based water repellant wax that doesn't completely harden but remains soft and pliable, and therefore doesn't crack, chip, or peel. It's also self-healing if scratched. Because of its nature, cavity wax wicks into welds and seams. Cavity wax is often used when restoring vehicles and is important to use in body areas that have been repaired after an accident.

How Is Cavity Wax Applied?

Cavity wax is applied by spraying and is available in aerosol can versions as well as in paint cans for use in compressor-driven wax spraying equipment like an auto body Schutz applicator-type gun. The surface is coated with about a millimeter of cavity wax for proper coverage. In some cases where the wax cannot reach the area to be protected by the nozzle of the spray gun or aerosol can, a piece of flexible hose, commonly called a spray wand, can be attached to reach the cavities. The hose can be fed or snaked around corners and into areas that were previously out of reach.

Spray wand inserted into cavity

A cone-shaped nozzle disburses a stream of cavity wax perpendicular to the hose to help fully coat the cavity. Spraying while pulling the wand from the cavity at a rate of about two inches per second works best. Also, as the extension cavity wax wand is pulled from a cavity, individuals using the spray gun should release the spray gun trigger to avoid overspray.

Close up of spray wand tip

Surface Prep and Precautions

Before the wax is applied, the surface should be as free as possible of grease, wax, and readily accessible loose scaly rust. When applying inside cavities, make sure that all drain holes remain open.

Cavity wax should not be applied to exhaust systems, as it will produce smoke and can be flammable. It's important to know that any grinding, cutting, or heating with a torch can cause the cavity wax to run. Any work which raises a part's temperature above 160°F should be done before cavity wax is applied.

KBS Cavity Coater

KBS Coatings offers Cavity Coater as a solution for providing rust protection in hard-to-reach areas. Cavity Coater is a single-step, super-penetrating corrosion inhibiting coating (CIC) designed for long-term protection of all metal surfaces. It provides a self-healing cavity wax film tested to render more than 4,000 hours of ASTM B-117 salt spray protection - over 4 times the protection of conventional cavity waxes. Cavity Coater resists road salt, alkaline solutions, and chemicals, and for especially hard-to-reach areas the Cavity Wand is offered to extend the reach of aerosol Cavity Coater with a reusable 36-inch hose that features a 360-degree spray tip. The Cavity Wand requires only a 1/4-inch hole to insert and is easily cleaned. Cavity Coater is available in aerosol, quart, gallon, and larger bulk sizes.

Frequently Asked Questions

Cavity wax is an excellent solution for providing rust protection in hard-to-reach areas and is perfect for brand new and older vehicles. KBS Coatings Cavity Coater product information is available here. Full application directions for Cavity Coater and the Cavity Wand can be found here.