What is the KBS 25-50 Gallon Tank Sealer Kit?
The KBS 25-50 Gallon Tank Sealer Kit is a complete three-step fuel tank restoration system that cleans, acid-etches, and permanently seals the inside of metal and fiberglass tanks holding 25 to 50 gallons. Each kit contains a gallon of KBS Klean, a gallon of RustBlast, and two quarts of Gold Standard Tank Sealer, enough to coat roughly 200 square feet of interior tank surface at 2 mils.
Up to 50 Gal
Tank Capacity
55–82°F
Ideal Application Temp
3 Steps
Klean, RustBlast, Seal
Gold Standard Fuel Tank Sealer is a single-component, moisture-cured coating that needs no hardener and no mixing. Gold Standard Tank Sealer stops rust and corrosion by forming a tough, fuel-impervious silver metallic film while simultaneously sealing small pinholes and leaking weld seams.
The two prep products in this kit do the work that makes the seal last. KBS Klean is a water-based, heavy-duty cleaner and degreaser that strips out old fuel varnish, gum, and oil residue. RustBlast is a powerful rust remover and metal etch that neutralizes remaining rust and leaves a zinc phosphate film for the sealer to grip. Sealing a tank without both prep steps is the single most common cause of coating failure.
This kit is sized for RV tanks, tractor tanks, diesel tanks, hold tanks, air compressor tanks, marine tanks, and any other tank in the 25 to 50 gallon range. Coverage varies with tank condition, substrate, and interior baffling.
Everything needed to clean, prep, and permanently seal a 25 to 50 gallon tank, in one box, with detailed instructions. Satisfaction guaranteed!
A customer tank before and after the KBS 3-Step System. Gold Standard Tank Sealer cures to a smooth, ceramic-like silver film at a minimum 3 mil dry thickness.
The KBS 25-50 Gallon Tank Sealer Kit contains a full gallon of KBS Klean cleaner and degreaser, a full gallon of RustBlast rust remover and metal etch, two quarts of Gold Standard Tank Sealer, nitrile gloves, a stir stick, and printed step-by-step directions. Nothing else needs to be purchased to clean, prep, and seal a tank up to 50 gallons.
- 1 Gallon of KBS Klean — Water-based heavy-duty cleaner and degreaser. Dilutes 1:1 with hot water and removes fuel varnish, gum, oil, and loose flaky rust.
- 1 Gallon of RustBlast — Acid metal etch and rust remover. Poured in full strength, it neutralizes remaining rust and leaves a zinc phosphate anchor pattern for the sealer.
- 2 Quarts of Gold Standard Tank Sealer — Single-component, moisture-cured silver metallic sealer. Covers roughly 200 square feet of interior surface at 2 mils.
- Nitrile Gloves — Gold Standard Tank Sealer stains skin permanently once cured, so gloves are not optional.
- Stir Stick — For lifting settled silver pigment off the bottom of the can without whipping air into the sealer.
- Detailed Printed Instructions — The full 3-step procedure, including drying, draining, and cure times.
Safety first: Always wear protective gloves and safety glasses, and always work in a well-ventilated area. Drain all fuel and remove the tank from the vehicle before beginning. Never attempt to seal a tank that is still mounted in a vehicle.
Gold Standard Tank Sealer is a single-component moisture-cured polymeric isocyanate that requires no hardener and no mixing ratio. Gold Standard Tank Sealer cures to a 76% solids, smooth ceramic-like silver film that is impervious to gasoline, diesel, ethanol blends, and most solvents, and it contains no methyl ethyl ketone.
- Single-Component Formula: No hardener, no catalyst, no mix ratio to get wrong. Stir, pour, coat, and drain.
- Fuel Impervious: Tested in continuous contact with 93 octane fuel, diesel fuel, xylene, MEK, brake fluid, and hydraulic fluid for 168 hours with no noticeable change.
- Alcohol and Ethanol Resistant: Stands up to modern alcohol-blended pump fuels that attack older tank liners.
- Seals Pinholes and Weld Seams: The sealer bridges and permanently seals small pinholes and leaking weld seams as it coats.
- Bonds Over Remaining Rust: Every last trace of rust does not need to be removed. Gold Standard Tank Sealer bonds to and permanently seals residual rust and corrosion.
- Flexible and Impact Resistant: The cured film expands and contracts with the tank rather than cracking, and resists impact and abrasion.
- Salt Water Tested: ASTM B-117 salt spray at 95°F and 5% salt for 2,000 hours with no noticeable change.
- Chemical Resistant: Holds up to acids, alkalis, salts, minerals, and solvents, including 40% hydrochloric acid and 20% phosphoric acid.
- Non-Flammable and MEK-Free: VOC not more than 250 g/l, flash point 103°F, and no methyl ethyl ketone in the formula.
Why Does the Tank Need Both KBS Klean and RustBlast First?
Every tank, new or old, carries oils, residues, and contaminants that block adhesion. KBS Klean removes the fuel varnish, gum, and oil film. RustBlast then etches the bare metal and leaves a zinc phosphate layer that the sealer keys into. Skipping either step is the leading cause of a tank liner letting go later.
The KBS 25-50 Gallon Tank Sealer Kit works on steel, aluminum, and fiberglass fuel tanks, plus oil tanks, utility tanks, diesel tanks, and non-potable water tanks in the 25 to 50 gallon range. Fiberglass tanks follow the same procedure with one change: RustBlast dwells for only 2 minutes instead of 30 to 60 minutes.
- Automotive & Truck
- Car and light truck fuel tanks, classic and restoration tanks, diesel saddle tanks, and auxiliary transfer tanks.
- RV, Tractor & Equipment
- Motorhome and travel trailer tanks, tractor and combine fuel tanks, skid steer and generator tanks, and air compressor tanks.
- Marine
- Steel, aluminum, and fiberglass boat fuel tanks and hold tanks. Fiberglass tanks must be dried completely and coated with no gaps.
- Shop, Farm & Utility
- Home heating oil tanks, farm storage and utility tanks, and non-potable water tanks.
- Tank Materials
- Steel, aluminum, and fiberglass. Gold Standard Tank Sealer is not intended for plastic or polyethylene tanks; see the plastic tank directions for that application.
- Fuel Types
- Gasoline, diesel, ethanol-blended pump fuels, and alcohol additives. Fiberglass tanks should avoid alcohol-blended fuels even after sealing.
Can Fiberglass Tanks Be Sealed With This Kit?
Yes. The procedure is identical except in Step 2, where RustBlast wets the fiberglass surface for only 2 minutes before being drained and rinsed. Because no rust is being dissolved, that RustBlast can be strained and saved for reuse. Fiberglass holds moisture, so forced air drying with a shop vac, fan, or blow dryer is critical before sealing.
Gold Standard Tank Sealer covers approximately 100 square feet per quart, or 400 square feet per gallon, at 2 mils on porous rusted surfaces. The two quarts in this kit therefore coat roughly 200 square feet of interior tank surface, which suits an average 25 to 50 gallon tank. Minimum recommended dry film thickness is 3 mils.
| Kit Component | Size Included | How Far It Goes |
|---|
| KBS Klean | 1 Gallon | Dilutes 1:1 with hot water, so 1 gallon makes 2 gallons of cleaning solution |
| RustBlast | 1 Gallon | Poured in full strength and drained, then strained and reused as needed |
| Gold Standard Tank Sealer | 2 Quarts | Approximately 200 sq. ft. total at 2 mils (100 sq. ft. per quart) |
Coverage varies. Interior baffles, heavy pitting, and severe corrosion all increase surface area and consume more sealer. Tank condition, substrate, and application technique change the result, so treat 25 to 50 gallons as a guideline rather than a hard limit.
Timing notes: Touch dry is 4 to 6 hours at 77°F and 50% humidity inside an enclosed tank with minimal airflow. Allow 96 hours for full cure before adding fuel. Seal the tank within 10 days of cleaning and prepping it.
Pro Tip: After coating, drain all excess sealer until the tank no longer drips, then rotate the tank side to side every 5 minutes while it sets. Puddled sealer traps gas underneath, foams, and can break loose later. The only fix at that point is stripping the tank and starting over.
KBS Gold Standard Tank Sealer differs from a two-part epoxy tank liner in that Gold Standard Tank Sealer is a single-component moisture-cured coating with no hardener and no mix ratio to get wrong. Gold Standard Tank Sealer also bonds directly over residual rust, which most epoxy liners require to be removed to bare metal first.
| | KBS Gold Standard Tank Sealer | Two-Part Epoxy Tank Liner |
|---|
| Mixing required | None, single component, stir and pour | Yes, resin plus hardener at a fixed ratio |
| Applied over residual rust | Yes, bonds to and seals remaining rust | Typically requires bare, rust-free metal |
| Coats needed | One thin coat, poured and drained | Commonly 2 to 3 coats |
| Prep included in the kit | Yes, KBS Klean and RustBlast both included | Varies, prep chemicals often sold separately |
| Ethanol resistance | Impervious to alcohol additives and ethanol blends | Varies by formula, older epoxies can soften |
| Full cure | 96 hours | Varies, commonly 24 to 72 hours |
A two-part epoxy liner is the better choice when the shop is humid or the job cannot wait, since epoxy cures by chemical reaction rather than atmospheric moisture and generally reaches full cure faster. Gold Standard Tank Sealer is moisture-cured, so it should not be applied in rainy or high-humidity conditions, and it needs the full 96 hours before fuel goes back in.
Applying the KBS 25-50 Gallon Tank Sealer Kit takes three steps: soak the tank with KBS Klean diluted 1:1 in hot water, etch it with full-strength RustBlast for 30 to 60 minutes, then pour in Gold Standard Tank Sealer, rotate to coat every surface, and drain all excess. Ideal application temperature is 55 to 82°F.
- Step 1 — KBS Klean (Clean)
- Drain the fuel and remove the tank from the vehicle. Remove floats, sending units, and filters, then seal all openings. Mix KBS Klean 1:1 with hot water, pour it in, and rotate the tank at intervals. Heavy gum and varnish may need 24 hours or more of soaking. Rinse until the water runs clear, then drain and dry.
- Step 2 — RustBlast (Etch)
- Pour the entire gallon of full-strength RustBlast into a dry tank. Roll and tip the tank every 5 minutes for a minimum of 30 minutes to 1 hour. Do not let RustBlast dry on the surface. Drain, rinse thoroughly, then dry completely with forced air. A white powdery zinc phosphate residue is normal and is what the sealer bonds to.
- Step 3 — Gold Standard Tank Sealer (Seal)
- Stir the can thoroughly, touching bottom to lift settled silver pigment. Never shake or whip the can. Pour the full contents in and slowly rotate the tank for up to 30 minutes until every surface is coated. Drain all excess until it stops dripping, then rotate side to side every 5 minutes. Allow 96 hours for full cure and test with water before refueling.
Read the Full Application Directions
Do not rush any step. Let the tank cool to room temperature before sealing, and never seal a tank sitting in direct sunlight. Heating a tank does not speed the cure and can hinder adhesion.
Clean up with KBS #1 Thinner only, and do it before the sealer dries. Cured Gold Standard Tank Sealer cannot be removed by any solvent. Remove sealer from threads and fuel lines immediately.
How Long Before I Can Put Fuel Back in the Tank?
Allow 96 hours for maximum cure before refilling with fuel. Touch dry happens at 4 to 6 hours at 77°F and 50% humidity, but touch dry is not cured. Let the tank air dry naturally in a well-ventilated area, out of direct sun and away from direct heat, and always test the tank with water before fuel goes back in.
Tank Sealer Application Directions & TDS
The full 3-step procedure with dwell times, drying requirements, fiberglass tank variations, and stripping instructions.
Read Article →
How to Avoid Common Tank Sealer Mistakes
The KBS Fix-It Guide for tank sealing: what goes wrong, why it goes wrong, and how to recover from it.
Read Article →
How Much Tank Sealer Do I Need?
Match your tank capacity to the right kit size so you buy enough sealer the first time.
Read Article →
Tank Sealer Chemical Resistance Guide
Spot-test results for Gold Standard Tank Sealer against fuels, acids, alkalis, and solvents over 168 hours of contact.
Read Article →
Patience When Using Tank Sealer
Why rushing the drying and draining steps is the most common reason a tank liner fails, and how to slow down.
Read Article →
Tank Sealer How-To Guides
Step-by-step walkthroughs for sealing a gas tank, from tank removal through the final cure.
Read Article →
Have questions before you buy? Find answers to the most common Tank Sealer Kit questions below — or
order the 25-50 Gallon Tank Sealer Kit now and get it shipped same day.
The KBS 25-50 Gallon Tank Sealer Kit is a complete three-step system that cleans, etches, and permanently seals fuel tanks holding 25 to 50 gallons. What sets it apart is that Gold Standard Tank Sealer is a single-component moisture-cured coating with no hardener and no mix ratio, and it bonds directly to residual rust rather than requiring the tank be stripped to bare metal. The kit includes the prep chemicals, so nothing else needs to be purchased.
This kit is sized for an average 25 to 50 gallon tank. Gold Standard Tank Sealer covers roughly 100 square feet per quart, or 400 square feet per gallon, at 2 mils on porous rusted surfaces, so the two quarts included cover approximately 200 square feet of interior surface. Heavy pitting, internal baffles, and severe corrosion all increase surface area and consume more sealer, so treat the gallon rating as a guideline.
Gold Standard Tank Sealer works on steel, aluminum, and fiberglass tanks. That covers automotive and truck fuel tanks, RV and tractor tanks, diesel tanks, marine and hold tanks, oil tanks, air compressor tanks, utility tanks, and non-potable water tanks. Fiberglass tanks follow the same procedure with one change in Step 2: RustBlast wets the surface for only 2 minutes instead of 30 to 60 minutes.
Allow 96 hours for maximum cure before refilling the tank with fuel. Average touch dry time is 4 to 6 hours at 77°F and 50% humidity inside an enclosed tank with minimal airflow, but touch dry is not the same as cured. Let the tank air dry naturally in a well-ventilated area out of direct sun and away from direct heat, and always test the tank with water before adding fuel.
Ideal application temperature is 55°F to 82°F, or 13°C to 28°C. Gold Standard Tank Sealer is a moisture-cured urethane, so use it only in moderate to dry atmospheric conditions and avoid sealing in rainy or humid weather. If the sealer cures too fast, gas gets trapped under the top layer and the surface bubbles. Let the tank cool to room temperature first and never seal a tank sitting in direct sunlight.
Drain the fuel, remove the tank from the vehicle, pull the fittings, and seal all openings. Step 1: mix KBS Klean 1:1 with hot water, soak and rotate, then rinse and dry. Step 2: pour in full-strength RustBlast and roll the tank every 5 minutes for 30 to 60 minutes, then rinse and dry completely with forced air. Step 3: stir the sealer, pour it in, rotate for up to 30 minutes, drain all excess, and cure for 96 hours.
No. Loose, flaky rust and scale must come out during the KBS Klean step, but it is not necessary to remove every last trace of rust before sealing. Gold Standard Tank Sealer bonds to and permanently seals remaining rust and corrosion. What matters far more is that the tank is completely free of oil and fuel residue, properly etched by RustBlast, and completely dry before the sealer goes in.
No. An old coating must be removed completely before the KBS 3-Step System is used, because Gold Standard Tank Sealer bonds to whatever is underneath it and a failing liner takes the new coating with it. KBS Strip is the most effective remover for a failed tank coating and works best when ambient and surface temperatures are above 70°F. Pour it in, rotate, drain, strain, and reuse it until the old liner is gone.
Use KBS #1 Thinner, and clean up immediately. Cured Gold Standard Tank Sealer cannot be removed by any solvent, so excess sealer must come off threads and fuel lines before it sets. Wear gloves to avoid skin contact and temporary staining. If sealer does contact skin, remove it right away with #1 Thinner or lacquer thinner followed by soap and water. Once it stains skin, only time will remove it.
Gold Standard Tank Sealer permanently seals pinholes and weld seams on its own. For anything larger than a pin tip, repair it before sealing: scuff the area with 320 grit and apply KBS NuMetal Epoxy Putty, then let it cure 12 hours. For exterior reinforcement of pinholes or weld seams, embed KBS BackBone Reinforcing Mesh into wet sealer and coat over it. Prep the inside and outside with KBS Klean and RustBlast first.
Simple Steps to Seal a Gas Tank with the KBS Tank Sealer System: the full 3-step process from cleaning through the final drain.
