Tank Sealer Application Directions - Tank Sealer TDS

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Tank Sealer is applied in three steps: clean with KBS Klean full strength, prep with RustBlast, then pour in a single coat of Tank Sealer and rotate the tank to coat every surface. Apply between 55 and 82 degrees F and allow the tank to sit undisturbed for a full 96 hours to cure. Tank Sealer forms a solid, leak-proof barrier that stops rust and resists fuel, ethanol, and corrosive vapors.

Importance of Tank Preparation:

Ideal application temperatures for Tank Sealer are 55 to 82 degrees F (13 to 28 degrees C). Tank Sealer is a moisture-cured urethane, so avoid applying in rain or high humidity. Trapped moisture and gas can cause bubbling in the cured film. If you are sealing a fiberglass tank, see the Fiberglass Tanks section below, since the process varies. If the tank was previously sealed with another product, that coating must be fully stripped first. See Stripping Old Coating below.

Step #1 - KBS Klean Cleaning:

Drain all fuel and remove the tank from the vehicle. Remove fittings and seal any openings with duct tape, rubber stoppers, or similar. Mix KBS Klean full strength, 1 part hot water to 1 part KBS Klean. Pour the mixture into the tank, seal the openings, and soak the tank while rotating it periodically. Heavy buildup may need up to 24 hours of soaking. Adding a handful of nuts, bolts, or a length of chain and shaking the tank helps agitate and loosen stubborn rust.

Strain the solution and repeat as needed. Use a flashlight to inspect for any remaining loose rust. Rinse the tank until the water runs clear, then dry it completely before moving to Step 2.

KBS Klean Dilution Ratio

Full strength, 1 to 1 with hot water, is correct for tank interior cleaning. The standard 10 to 1 dilution is for general cleaning jobs outside of tanks.

Step #2 - RustBlast Surface Prep:

Pour RustBlast into the tank at full strength, no dilution. Roll and tip the tank every 5 minutes for a minimum of 30 to 60 minutes. Do not let RustBlast dry on the surface. Drain, capture, and repeat as needed for heavier rust. It is not necessary to remove every last bit of rust; Tank Sealer bonds directly to any remaining rust.

After the final rinse, the tank must dry completely before sealing. Use forced air, a shop vac, blow dryer, or fan, to speed drying. A white, powdery residue left behind by RustBlast is normal zinc phosphate and is beneficial to the sealing process; do not wash it away.

For pinholes or small holes larger than a pinhole, repair with NuMetal Epoxy Putty before sealing. See Exterior Tank Patching below for the full process. Allow the tank to cool to room temperature before moving to Step 3, and never seal in direct sunlight.

Step #3 - Tank Sealer Sealing:

Seal the tank within 10 days of completing prep. Stir Tank Sealer thoroughly before use, touching the bottom of the can and lifting rather than whipping or shaking it, to avoid introducing air bubbles. Pour the entire contents into the tank, then rotate and roll the tank for up to 30 minutes to coat every interior surface in a single thin coat.

Drain all excess sealer completely. Continue rotating the tank side to side every 5 minutes as it drains to avoid pooling. Foaming or bubbling during this stage is a warning sign of trapped gas and may require a full strip and redo. Any leftover sealer should be used immediately for exterior patching; drained sealer cannot be saved or reused. Remove excess sealer from threads and fuel lines before it cures.

Leave the lid off the can used to catch the drained sealer until it has fully hardened, since a sealed lid can build pressure. Let the tank air-dry naturally away from direct sun and heat. Heating the tank does not speed curing and may hinder adhesion. Allow a full 96 hours for maximum cure. Always test the tank with water before adding fuel.

Exterior Tank Patching:

For pinholes and weld seams, use BackBone Reinforcing Mesh. Prep both the outside and inside of the repair area and let it dry completely. Seal the inside of the tank first, then apply a thin exterior layer of Tank Sealer, embed the mesh into it, and apply a second thin coat outward from the center once the first has set.

For holes larger than a pinhole, use NuMetal Epoxy Putty. Clean and prep the area, let it dry, then scuff with 320 grit sandpaper. Allow NuMetal 12 hours to cure before sealing the interior. Apply a thin exterior reinforcement coat of Tank Sealer after the interior is sealed and drained.

Fiberglass Tanks:

Fiberglass tanks follow the same 3-step system with one key variance in Step 2: limit RustBlast contact to only 2 minutes rather than the standard 30 to 60 minutes, since RustBlast is not dissolving rust on fiberglass and prolonged contact can weaken the resin. Because RustBlast is not consuming rust on this surface, it can be saved and reused. The tank must be completely dry before sealing, since fiberglass holds moisture longer than metal.

Full, thorough coverage is critical on fiberglass. Any exposed area is vulnerable to alcohol-blended fuels, so KBS recommends avoiding alcohol-blended fuels in fiberglass tanks even after sealing. See the Tank Sealer Fix-It Guide for troubleshooting.

Stripping Old Coating:

If a tank was previously sealed with another product, that coating must be fully removed before starting the 3-step system. Use KBS Strip between 60 and 85 degrees F; it works best above 70 degrees F, the warmer, the better. Pour it in, rotate the tank, and repeat applications as needed. A tweezers-style tool helps pull out loosened chunks of old coating.

KBS Strip can be strained and reused as many times as needed. Rinse thoroughly afterward and repeat the process if any old sealer remains. Once the tank is fully stripped, proceed to Step 1 of the 3-step system above. Fiberglass tanks need only minimal stripper contact time, since extended contact risks weakening the resin. KBS Strip will also remove exterior paint, so protect any finish you want to keep.

Clean Up:

Use KBS #1 Thinner for immediate cleanup of tools and equipment. Tank Sealer cannot be removed once it cures, so clean up right away. Wear gloves while cleaning. For skin contact, use #1 Thinner or lacquer thinner followed by soap and water. Gold Standard stains will only fade with time.

Technical Data:

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