What is KBS UnderCoat Water Based Asphalt?
KBS UnderCoat Water Based Asphalt is a low VOC, asphalt based undercoating that seals wheel wells, frames, floor pans, and fenders against road salt and moisture while deadening road noise and vibration. KBS UnderCoat Water Based Asphalt contains no solvents, sprays, brushes, or rolls on, and is dry to the touch in 30 to 60 minutes.
30 to 60 Min
Dry to Touch
100 to 120 sq ft
Coverage per Gallon
KBS UnderCoat Water Based Asphalt lays down a tough, 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 moisture and corrosion resistance.
Sound control is the second job. KBS UnderCoat Water Based Asphalt deadens road noise and vibration carried through floor pans, wheel wells, and quarter panels, and the cured film stays paintable when the underside needs to match body color.
Manufactured in Valparaiso, Indiana. Orders placed by 3 PM Central ship the same day. Satisfaction guaranteed!
KBS UnderCoat Water Based Asphalt protects wheel wells, gas tanks, frames, quarter panels, fenders, undercarriages, hoods, decks, and floor pans. KBS UnderCoat Water Based Asphalt goes on the areas that take road salt, water, and stone impact, and one gallon covers 100 to 120 square feet of that surface.
- Wheel Wells and Fenders
- The highest salt and stone exposure on the vehicle, and the most common failure point on an untreated underside.
- 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 to the underside of a hood.
- Gas Tanks
- Protects the exterior of a tank where road spray collects.
Heat limit: Do not use KBS UnderCoat Water Based Asphalt on surfaces that touch direct heat or high temperatures, such as mufflers and exhaust components.
KBS UnderCoat Water Based Asphalt combines corrosion protection and sound deadening in a low VOC coating that contains no solvents. KBS UnderCoat Water Based Asphalt bonds to bare metal, painted surfaces, and cured RustSeal, applies by spray, brush, or roller, and is dry to the touch in 30 to 60 minutes.
- Asphalt Based Formula: A tough, flexible film rather than a brittle shell.
- Low VOC, No Solvents: A water based formula that cleans up with soap and water or KBS Klean.
- Sound Deadening: Reduces road noise and vibration through floor pans, wheel wells, and quarter panels.
- Chip Resistant: The cured film flexes with the panel instead of fracturing under gravel strikes.
- Corrosion Protection: Seals the surface against road salt, brine, and moisture.
- Excellent Adhesion: Bonds to bare metal and to sound painted surfaces.
- Spray, Brush, or Roll: Works with a Schutz style spray gun, a synthetic brush, or a synthetic roller.
- Uniform Appearance: An even matte black finish that stays paintable.
- Easy to Apply: Dry to the touch in 30 to 60 minutes and fully cured in 24 hours.
KBS UnderCoat Water Based Asphalt bonds to clean bare metal, sound painted surfaces, fiberglass, and cured RustSeal. The surface must be free of dirt, dust, oil, grease, loose paint, and loose rust, and KBS Klean diluted 5 to 1 is the recommended cleaner for that prep step.
- Bare and Painted Metal
- Clean, dry metal takes the coating directly. Remove any loose or flaking paint first, because the coating bonds to whatever is underneath it.
- Fiberglass
- KBS UnderCoat Water Based Asphalt helps keep road salt from attacking fiberglass the same way it protects metal.
- Cured RustSeal
- KBS UnderCoat Water Based Asphalt has excellent adhesion to cured RustSeal, which makes it the finishing layer of the KBS 3-Step System on a rusted undercarriage.
A gallon of KBS UnderCoat Water Based Asphalt typically covers 100 to 120 square feet, a quart covers 25 to 30 square feet, and a 5 gallon pail covers 500 to 600 square feet. Coverage varies with how smooth the surface is, and rough or pitted metal uses more material than smooth panels.
KBS UnderCoat Water Based Asphalt coverage by size
| Size | Typical Coverage |
|---|
| Quart (32 oz) | 25 to 30 sq. ft. |
| Gallon (128 oz) | 100 to 120 sq. ft. |
| 5 Gallon Pail (640 oz) | 500 to 600 sq. ft. |
Recoat window: wait 30 to 60 minutes between light coats when spraying. On a brushed or rolled job, apply the second coat after 2 hours.
Pro Tip: Measure the area first, then divide by the coverage figure. A gallon is a good starting size for a whole underside, and the 5 gallon pail suits trucks, trailers, and multi vehicle jobs.
Water based undercoating differs from solvent based undercoating mainly in cure time and clean up. KBS UnderCoat Water Based Asphalt is low VOC, thins with water, and cleans up with soap and water or KBS Klean, but it takes about 24 hours to fully cure, against 2 to 4 hours for the solvent based KBS UnderCoat formulas.
KBS UnderCoat water based and solvent based formulas compared
| | KBS UnderCoat Water Based Asphalt | KBS UnderCoat Solvent Based |
|---|
| VOC | Low VOC, no solvents | Solvent based |
| Dry to touch | 30 to 60 minutes | 60 minutes |
| Full cure | About 24 hours | 2 to 4 hours |
| Thins with | Water | KBS #1 Thinner |
| Clean up | Soap and water, or KBS Klean | KBS #1 Thinner |
| Paintable after cure | Yes | Yes |
The solvent based formula is the better choice when a job has to be fully cured the same day, since it reaches full cure in 2 to 4 hours. The water based formula is the better choice when low VOC and soap and water clean up matter more than cure speed. KBS UnderCoat Solvent Asphalt and KBS UnderCoat Solvent Rubberized are the solvent based options.
Apply KBS UnderCoat Water Based Asphalt after cleaning the surface with KBS Klean diluted 5 to 1 and letting it dry. Spray it through a Schutz style gun or brush or roll it on in light coats, waiting 30 to 60 minutes between sprayed coats, and work between 70 and 90 degrees F with 50 percent or less humidity.
- 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 finish.
- Step 2: Spray Application
- Shake the can well. Spray quarts and gallons through the KBS Schutz Underseal Spray Gun or an auto body Schutz style applicator gun. The contents can be poured into a clean pot or an empty dome quart can that fits the gun. Thinning is not usually needed, and water thins the water based formula if required.
- Step 3: Brush or Roll Application
- Mix thoroughly so any settled pigment is re-dispersed, then use a high quality synthetic brush or synthetic roller. The first coat dries to the touch in 1 to 2 hours and the second coat goes on after 2 hours.
- Step 4: Cure and Clean Up
- Allow a minimum of 24 hours to fully dry and keep the coating out of rain or moisture during that time. Clean the gun right away with KBS Klean diluted 1 to 1 with warm water.
Safety: Always wear protective gloves and safety glasses, work in a well ventilated area, and heed all labeled warning and caution notices on the product. Dry and recoat times assume 70 degrees F and 50 percent relative humidity, so allow more time at cooler temperatures.
KBS UnderCoat Water Based Asphalt is the finishing layer of the KBS 3-Step Rust Prevention System, applied over cured RustSeal on a rusted undercarriage. KBS Klean cleans first, RustSeal seals the rust second, and KBS UnderCoat adds chip resistance and sound deadening on top.
- Step 1: KBS Klean
- Water based degreaser that strips grease, oil, and road film so the following coats bond.
- Step 2: RustSeal
- Single component rust encapsulating coating that seals rusted metal against moisture and oxygen.
- Step 3: KBS UnderCoat Water Based Asphalt
- Applied over the cured RustSeal for chip resistance, sound deadening, and a matte black finish.
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
Application directions, coverage, cure times, and clean up for the water based and solvent based KBS UnderCoat formulas.
Read Article →
KBS UnderCoat Questions and Answers
Short answers on sound deadening and on how Schutz gun pressure changes the finished texture.
Read Article →
The KBS 3-Step Rust Prevention System
How KBS Klean, RustBlast, and RustSeal work together, and where UnderCoat fits as the finishing layer.
Read Article →
RustSeal Rust Encapsulating Coating
The coat that goes under KBS UnderCoat on rusted metal, and why the order matters on an undercarriage.
Read Article →
KBS Schutz Underseal Spray Gun
The applicator that sprays UnderCoat from a dome style quart can, with a 48-inch 360-degree wand for cavities.
Read Article →
KBS UnderCoat Solvent Asphalt
The solvent based asphalt version of KBS UnderCoat, with a 2 to 4 hour full cure and thinner clean up.
Read Article →
Have questions before you buy? Find answers to the most common KBS UnderCoat Water Based Asphalt questions below, or
order KBS UnderCoat now.
The cost of undersealing a car comes down to how much area you coat and which size you buy. KBS UnderCoat Water Based Asphalt covers 100 to 120 square feet per gallon and 25 to 30 square feet per quart, so measure the surface, divide by the coverage figure, and pick the size that fits. Doing the work yourself with a brush, roller, or Schutz spray gun avoids shop labor. Current prices for each size are shown in the size selector at the top of this page.
Under a car, the best anti-rust protection is a three layer system. Clean the metal with KBS Klean, seal rusted or bare steel with RustSeal, and let the RustSeal cure. Then apply KBS UnderCoat Water Based Asphalt over the cured RustSeal for chip resistance and sound deadening. Inside frame rails and rocker panels, use Cavity Coater instead of a thick undercoating.
Car undercoatings are made from asphalt, synthetic rubber, or wax and oil based materials. KBS UnderCoat Water Based Asphalt is an asphalt based undercoating in a low VOC water based formula. It dries to a flexible matte black film that seals out road salt and moisture, deadens road noise, and stays paintable.
Water based undercoating cleans up with soap and water, thins with water, and has no solvents, while solvent based undercoating cleans up with KBS #1 Thinner. The tradeoff is cure time: KBS UnderCoat Water Based Asphalt is dry to the touch in 30 to 60 minutes and fully cures in about 24 hours, while the solvent based KBS UnderCoat formulas reach full cure in 2 to 4 hours.
KBS UnderCoat Water Based Asphalt is typically dry to the touch in 30 to 60 minutes and fully cured in 24 hours. Wait 30 to 60 minutes between light coats. On a brushed or rolled job the first coat dries to the touch in 1 to 2 hours, the second coat goes on after 2 hours, and the second coat can be top coated after 24 hours. Times assume 70 degrees F and 50 percent relative humidity, and cooler or more humid air takes longer.
Clean the surface with KBS Klean diluted 5 to 1, remove loose paint and rust, let it dry completely, and mask off anything that should stay clean. Shake the can well, then spray the quart or gallon through a KBS Schutz Underseal Spray Gun, or mix it thoroughly and apply it with a high quality synthetic brush or roller. Apply light coats and work between 70 and 90 degrees F with 50 percent or less humidity.
Yes. KBS UnderCoat Water Based Asphalt is paintable once it has cured. On a brushed or rolled application, the second coat can be top coated after 24 hours, and the surface needs a minimum of 24 hours to fully dry. Do not let the fresh coating see rain or moisture within 24 hours.
Do not apply KBS UnderCoat Water Based Asphalt to surfaces that come into direct contact with heat or high temperatures, such as mufflers and exhaust components. Mask off the finish and any parts that should stay clean, because overspray lands easily, and always wear gloves and safety glasses in a well ventilated area.
A gallon of KBS UnderCoat Water Based Asphalt typically covers 100 to 120 square feet, a quart covers 25 to 30 square feet, and a 5 gallon pail covers 500 to 600 square feet. Coverage depends on how smooth the surface is, and rough or pitted metal uses more material.
Clean the spray gun immediately after use with KBS Klean diluted 1 to 1 with warm water. Wipe excess coating off unwanted surfaces right away with the same mixture while it is wet. Once the coating has dried, KBS #1 Thinner removes it, and soap and water also removes excess coating while it is still wet.
