What is KBS UnderCoat Aerosol?
KBS UnderCoat Aerosol is a solvent based undercoating in a spray can that seals wheel wells, frames, gas tanks, and floor pans against road salt and moisture while deadening road noise. KBS UnderCoat Aerosol comes in a Rubberized or an Asphalt formula, covers 16 to 20 square feet per can, and dries to the touch in 60 minutes.
16 to 20 sq ft
Coverage per Can
KBS UnderCoat Aerosol lays down a very tough, yet flexible matte black film with excellent adhesion to bare metal and painted surfaces. The film helps keep road salt from eating away at a vehicle's metal and fiberglass, and it adds durable moisture and corrosion resistance at an economical cost.
Sound control is the second job. KBS UnderCoat Aerosol reduces road noise and vibration through floor pans, wheel wells, and quarter panels, and the spray can needs no spray gun or compressor, which suits touch ups, single wheel wells, and spot repairs.
Made in the USA in Valparaiso, Indiana. Orders placed by 3 PM Central ship the same day. Satisfaction guaranteed!
KBS UnderCoat Aerosol protects wheel wells, gas tanks, frames, quarter panels, fenders, undercarriages, hoods, decks, and floor pans. KBS UnderCoat Aerosol goes on the areas that take road salt, water, and stone impact, and one can covers 16 to 20 square feet of that surface.
- Wheel Wells and Fenders
- The highest salt and stone exposure on the vehicle. A can or two handles a pair of wheel wells without setting up a spray gun.
- Frames and Undercarriages
- Seals frame rails and cross members against standing moisture and winter brine.
- Floor Pans
- Blocks corrosion from below and cuts the road noise that comes straight through a bare pan.
- Quarter Panels, Hoods, and Decks
- Coats the inner surfaces and undersides that trap moisture behind the visible bodywork, and adds sound deadening under a hood.
- Gas Tanks
- Protects the exterior of a tank where road spray collects under the vehicle.
Heat limit: KBS UnderCoat Aerosol is not for surfaces that come in direct contact with heat or high temperatures, such as mufflers and exhaust components.
KBS UnderCoat Aerosol combines corrosion protection and sound deadening in a spray can, with a choice of Rubberized or Asphalt formula. KBS UnderCoat Aerosol bonds to bare metal, painted surfaces, and cured RustSeal, dries to the touch in 60 minutes, can be handled in 2 hours, and fully cures in 2 to 4 hours.
- Sound Deadening: Reduces road noise and vibration through floor pans, wheel wells, and quarter panels.
- Chip Resistant: A tough, yet flexible film that takes gravel strikes.
- Corrosion Protection: Seals the surface against road salt, brine, and moisture.
- Excellent Adhesion to Metal: Bonds to clean bare metal and to fiberglass.
- Excellent Adhesion to Painted Surfaces: Goes over sound paint and over cured RustSeal.
- Fast Dry: Dry to the touch in 1 hour and ready to handle in 2 hours.
- Easy to Apply: Sprays straight from the can, with no gun, compressor, or thinning.
- Uniform Appearance: An even matte black finish. The Rubberized formula is paintable. The Asphalt formula is not, because asphalt typically bleeds through a topcoat.
- Can or Case: A 16 oz Rubberized can or an 18 oz Asphalt can, sold singly or in a case of 12.
Should I Choose Rubberized or Asphalt UnderCoat Aerosol?
Choosing between the KBS UnderCoat Aerosol formulas is mostly personal preference, and often a matter of matching the original factory finish. Older vehicles typically left the factory with an asphalt undercoating, while newer vehicles tend to have a rubberized finish. If you plan to paint over the undercoating, choose Rubberized: asphalt typically bleeds through a topcoat.
One can of KBS UnderCoat Aerosol covers 16 to 20 square feet, and a case of 12 cans covers about 190 to 240 square feet. Coverage varies with how smooth the surface is, so rough or pitted metal and heavier coats use more material than smooth, clean panels.
KBS UnderCoat Aerosol coverage by purchase size
| Size | Typical Coverage |
|---|
| 1 Aerosol Can | 16 to 20 sq. ft. |
| Case of 12 Aerosol Cans | About 190 to 240 sq. ft. |
Recoat window: apply light coats and wait about 10 minutes between coats. The coating is dry to the touch in 60 minutes and fully cured in 2 to 4 hours.
Pro Tip: Measure the area first and divide by 16 to plan conservatively. For a whole underside, compare the case price with a gallon of bulk KBS UnderCoat, which covers 100 to 120 square feet through a Schutz gun.
KBS UnderCoat Aerosol and bulk KBS UnderCoat differ mainly in equipment and job size. KBS UnderCoat Aerosol sprays straight from the can and covers 16 to 20 square feet, while a gallon of bulk KBS UnderCoat covers 100 to 120 square feet, about as much as 6 aerosol cans, but needs a Schutz style spray gun or a brush or roller.
KBS UnderCoat Aerosol and bulk KBS UnderCoat compared
| | KBS UnderCoat Aerosol | Bulk KBS UnderCoat (Quart and Up) |
|---|
| Equipment needed | None, sprays from the can | Schutz style spray gun, or a synthetic brush or roller |
| Coverage per container | 16 to 20 sq. ft. per can | 25 to 30 sq. ft. per quart, 100 to 120 sq. ft. per gallon |
| Time between coats | About 10 minutes | 2 hours when brushed or rolled |
| Formulas | Rubberized or Asphalt, solvent based | Solvent Rubberized, Solvent Asphalt, or Water Based Asphalt |
| Clean up | Invert the can and spray the tip clear | Clean the gun with KBS #1 Thinner, or KBS Klean and water for the water based formula |
Bulk KBS UnderCoat is the better choice for a full underside or a fleet job, since one gallon covers about as much as 6 cans. See KBS UnderCoat Solvent Rubberized, KBS UnderCoat Solvent Asphalt, and KBS UnderCoat Water Based Asphalt.
Apply KBS UnderCoat Aerosol to a surface cleaned with KBS Klean diluted 5 to 1 and dried. Shake the can for at least 60 seconds after the agitator ball moves freely, hold it 10 to 12 inches from the surface, and spray light, uniform coats about 10 minutes apart, ideally between 70 and 90 degrees F.
- Step 1: Prepare the Surface
- Remove loose paint, rust, oil, and grease. Clean with KBS Klean diluted 5 to 1, let the surface dry thoroughly, and mask off the area to avoid overspray on the auto finish.
- Step 2: Shake and Spray
- Shake the can for at least 60 seconds after the agitator ball moves freely. Hold the can 10 to 12 inches from the surface and apply a uniform coat.
- Step 3: Build Light Coats
- Apply light coats, waiting about 10 minutes between coats. The coating is dry to the touch in 60 minutes and fully cured in 2 to 4 hours.
- Step 4: Clear the Spray Tip
- Turn the can upside down and spray until no more coating appears. If the tip clogs, remove it and clean it with a fine wire, then replace it with the can pointed away from you.
Safety: KBS UnderCoat Aerosol is solvent based, extremely flammable, and under pressure. Always wear protective gloves and safety glasses, always work in a well ventilated area, and heed all labeled warning and caution notices. For best results, spray between 70 and 90 degrees F with 50 percent or less humidity.
KBS UnderCoat Aerosol goes over cured RustSeal on an underbody job, and Cavity Coater goes on last inside frame rails and rockers. KBS Klean and RustBlast prepare the metal, RustSeal seals the rust, and KBS UnderCoat Aerosol adds chip resistance and sound deadening on top.
- Step 1: KBS Klean and RustBlast
- Clean off grease, oil, and road film, then treat the rusted metal, as in the KBS 3-Step System.
- Step 2: RustSeal
- Seals bare and rusted metal. KBS UnderCoat Aerosol has excellent adhesion to cured RustSeal.
- Step 3: KBS UnderCoat Aerosol
- Applied over the cured RustSeal for chip resistance, sound deadening, and a matte black finish.
- Step 4: Cavity Coater
- Goes on last, after the exterior coatings have fully cured, inside frame rails, rocker panels, and other enclosed cavities.
See the KBS 3-Step System
Video Guides
The KBS how-to library covers rust prevention, prep, and coating application across the product line.
KBS UnderCoat Directions and TDS
Aerosol and bulk application directions, coverage, cure times, and clean up for every KBS UnderCoat formula.
Read Article →
KBS UnderCoat Questions and Answers
Short answers on sound deadening and on how spray pressure changes the finished texture.
Read Article →
The KBS 3-Step Rust Prevention System
How KBS Klean, RustBlast, and RustSeal work together before KBS UnderCoat goes on.
Read Article →
RustSeal Rust Preventive Coating
The coat that goes under KBS UnderCoat on rusted metal, and why the order matters on an undercarriage.
Read Article →
Cavity Coater Cavity Wax
Rust protection for the inside of frame rails, rockers, and doors, applied after the undercoating cures.
Read Article →
All KBS Undercoatings
Rubberized and asphalt undercoating in aerosol, quart, gallon, and larger sizes, side by side.
Read Article →
Have questions before you buy? Find answers to the most common KBS UnderCoat Aerosol questions below, or
order KBS UnderCoat Aerosol now.
The cost of spraying an undercarriage yourself comes down to how much area you coat. One can of KBS UnderCoat Aerosol covers 16 to 20 square feet, so measure the area, divide by 16, and buy that many cans, or a case of 12. For a full underside, a gallon of bulk KBS UnderCoat covers 100 to 120 square feet through a Schutz gun. Doing the work yourself avoids shop labor, and current prices are shown in the selector at the top of this page.
Dry times vary by brand and formula, so check the label of the product you use. KBS UnderCoat Aerosol is dry to the touch in 60 minutes, can be handled in 2 hours, and reaches full cure in 2 to 4 hours, with about 10 minutes between light coats. These times are based on 70 degrees F and 50 percent relative humidity, and cooler air takes longer.
Yes, when the surface is prepared first. Undercoating clean, sound metal protects it from road salt, moisture, and stone chips, and KBS UnderCoat Aerosol also deadens road noise. Clean the underside with KBS Klean, seal any rusted metal with RustSeal and let it cure, then spray KBS UnderCoat Aerosol over it. Keep it off exhaust parts, brake components, moving parts, and rubber bushings.
No. An oil spray typically leaves a wet, oily film rather than drying to a coating, while an undercoating such as KBS UnderCoat Aerosol dries to the touch in 60 minutes and cures to a tough, flexible black film that resists chips and deadens road noise. For the inside of frame rails and rocker panels, KBS recommends Cavity Coater rather than a thick undercoating.
KBS UnderCoat Aerosol is a solvent based undercoating in a spray can, offered in a Rubberized or an Asphalt formula. KBS UnderCoat Aerosol protects wheel wells, frames, gas tanks, and floor pans from road salt and moisture, deadens road noise and vibration, and dries to a matte black finish. It is sold as a single can or a case of 12.
Clean the surface with KBS Klean diluted 5 to 1, remove loose paint and rust, let it dry, and mask off the auto finish. Shake the can for at least 60 seconds after the agitator ball moves freely, hold it 10 to 12 inches from the surface, and apply light, uniform coats about 10 minutes apart. Work between 70 and 90 degrees F with 50 percent or less humidity.
No primer is required. KBS UnderCoat Aerosol bonds to clean bare or painted metal and fiberglass on its own. For the best long term rust protection on bare or rusted metal, treat the surface first with the KBS 3-Step System of KBS Klean, RustBlast, and RustSeal, then spray KBS UnderCoat Aerosol over the cured RustSeal.
One can of KBS UnderCoat Aerosol covers 16 to 20 square feet, and a case of 12 covers about 190 to 240 square feet. Divide the area by 16 to plan conservatively, since rough or pitted metal and heavier coats use more material. When the job needs more than about 6 cans, a gallon of bulk KBS UnderCoat covering 100 to 120 square feet is usually the better buy.
Do not spray KBS UnderCoat Aerosol on surfaces that come in direct contact with heat or high temperatures, such as mufflers and exhaust components. Mask off the auto finish, brake components, driveshafts, and other moving parts, and keep it off rubber bushings, weatherstripping, and any surface that needs to stay flexible or friction free.
Clean the spray head right after use by turning the can upside down and spraying until no more coating appears. If the spray head clogs, remove it and clean it with a fine wire, then replace it carefully with the can and spray head pointed away from you. Wipe overspray off unintended surfaces right away with KBS #1 Thinner.
