Epoxy Gas (Fuel) Tank Sealer

Epoxy Gas (Fuel) Tank Sealer


Total volume of the 2 parts is about 700mL

Permanently Repairs Steel, Aluminum, Fiberglass and Plastic Gas Tanks

Price: $82.95


 This Item is a HAZMAT item.
We cannot ship this overseas or to some very remote locations in Australia. 
We cannot ship this item to a PO Box or parcel locker it must be delivered to a residential or business address. 

Because it is a Hazardous item, couriers cannot guarantee delivery times as they have to manage compatibility of all materials they carry. This does not generally affect the delivery of aerosols.




Epoxy Gas (Fuel) Tank Sealer


Total volume of the 2 parts is about 700mL, and it will cover approximately 2.3 square meters.

Permanently Repairs Steel, Aluminum, Fiberglass and Plastic Gas Tanks


Phenol Novolac Epoxies are a new breed of chemical resistant materials, able to withstand permanent immersion of many harsh solvents, fuels and oils. This Epoxy has much better bond strength than single component products, with strengths of up to 3000 PSI, and this higher strength reduces the need for a clinically clean surface, as the epoxy actually prefers to bond to a rough rusty surface. Our new phenol novolac is more thixotropic, which means it 'hangs' on the tank walls during the coating process. This gives a thicker overall coating. There is more volume of material in the kit to allow for this.

What else can you use Gas Tank Sealer for?

A corrosion and chemical resistant coating. ie: battery compartments.
A high strength adhesive where plenty of working time is needed.
A potting compound, to encapsulate electronics
A non-skid surface, just bed in aluminum oxide.
Relining old potato peeler machines (Hobart type) - coat liner and bed in aluminum oxide.
Repair leaks in concrete vessels, Add fine sand to make a mortar.
Bonds to almost anything except polyethylene. Bonds to Wood, plastic, rubber, concrete, metals.
Making high quality molds - virtually no shrinkage on curing.
Thin cross section repair of sheared parts, such as; broken cups, dishes, or a split leg on a chair.



Application Instructions

This applies to both metal and fiberglass tanks.



See below for current MSDS


  1. All traces of oil and gasoline should first be removed by going to Step 2 for plastic tanks or Step 3 for metal tanks. If you should decide to use acetone when doing a fiberglass or plastic tank use extreme caution. Do not allow solvents to stay in the tank over 10 minutes. Dispose of the contaminated solution. Allow to dry.
  2. For Plastic or Fiberglass tanks: wash the tank with Dish Washing Soap, Hot Water and the drywall screws. These will rough up the surface. Rinse with Hot water and allow to thoroughly dry then go to step 5.
  3. For Steel tanks place a hand full of drywall screws with about a pint of acetone or lacquer thinner into the tank and shake them around vigorously for several minutes. These will dislodge any loose particles of rust, and in the case of plastic/fiberglass, rough up the surface. Dispose of the contaminated solution. Allow to dry.
  4. ADDITIONAL STEP FOR ALUMINUM TANKS: Add two tablespoons of LYE (Drano, Caustic Soda) to four litres of water. ADD LYE TO WATER, NOT WATER TO LYE. WEAR PROTECTIVE GEAR. Slosh the solution around in the tank for 30 seconds. Pour solution out and dispose. Rinse with water and pour off. Add 250mL of vinegar into a litre of water and slosh around in tank for 30 seconds. This neutralizes the lye. Pour off and rinse with water. Allow to dry.
  5. Apply duct tape or masking tape to any weeping seams, holes or porous areas.  This will stop any Gas Tank Sealer from oozing out, and will allow it to bridge over the hole. Plug the outlet ports with putty or Play-Doh.
  6. If the tank has a good paint job, protect it from resin spillage by wrapping in a layer of GLADWRAP, then a layer of ALUMINUM FOIL, then another layer of GLADWRAP.




Mixing ratio is 2 parts of A to 1 part B. Gas Tank Sealer resins should be at room temperature. Store your resin and gas tank at room temperature for 12-24 hours before mixing, so that it is at the correct temperature. Resin colder than 21oC will make resin thick and not flow well, hotter than 30oC will make it runny, so it doesn’t stick to the sides well and it will cure too quickly. The tank and the resin should be at the same temperature. If the tank is hotter than the resin, it will cure the resin faster, reducing your working life and coverage. Resins stored in a garage that is 32°C, used at that temperature, would HALF the working time or worse. At 21°C, the material will have gelled in 30 minutes, so it is important to have wetted the tank walls with the sealer within 10-15 minutes of mixing.

Mix the sealer thoroughly in a suitable container. A clean ice cream container is ideal. Continue to so that the epoxy is completed mixed (approx. 2 minutes) (Coverage will depend entirely on the total surface area of the tank, not the volume) 

There is NO relationship of volume to surface area, i.e.:                 

Tank 1: 30cm x 30cm x 30cm = 27 litres,  surface area =5400cm2    

Tank 2: 30cm x 900cm x 1m   = 27 litres,  surface area = 54180cm2

IT IS NOT RECOMMENDED TO TRY TO USE THE KIT TO TREAT TWO SMALLER TANKS. MOST FAILURES OCCUR FROM IMPROPER MEASURING AND MIXING. You may apply a second application within 24 hours if you want to use up the resin. This is, of course, good insurance on a bad tank, or one with many baffles etc.

Apply the sealer IMMEDIATELY after mixing completely. Waiting 5-10 mins will reduce your working time and coverage rates, as the resin will have already started to cure.

In the event that the viscosity is too thick from working in higher temperatures which is inevitable, you can add a small amount of Xylene or lacquer thinner to the mix (no more than 5% - i.e. 30mL in the motorcycle kit, 60mL in the car kit). This serves to retard the cure cycle and thin the sealer somewhat to allow easier coating coverage.


  1. Pour into the tank, then immediately seal up the filler hole with GLADWRAP and an elastic band.  Rotate the tank around in every direction for several minutes to obtain a good layer of Gas Tank Sealer over all surfaces. Remove the filler cap, GLADWRAP seal, and pour out any excess.  Allow to drain upside down for a few minutes.
  2. If you have a built in fuel filter, blow air into the fuel line port for about 10 minutes.  This will clear the filter of any Gas Tank Sealer.
  3. Trim up any excess material as soon as the Gas Tank Sealer becomes plastic like.  This can be scraped out with a sharp knife at this point (usually about 40-60 Min after mixing) Place the tank in a warm 21-32 oC place and allow to cure for 24-36 hours before putting gasoline in the tank.
  4. If you want, or need to apply a second coat, you must do so while the first coat is still tacky (usually within 24 hours)
  5. If you can elevate the temperature of the tank to 60 oC for 4 hours, this will ‘post cure’ the resin and the tank may be put into immediate service.

A few weeks ago you sent me your gas tank sealer kit. In the meantime, I have tried it and I just wanted to tell you that IT'S A GREAT PRODUCT! It worked perfectly well! Now I have a perfect gas tank again for about 40 US$ (including spray paint etc.). A local repair shop wanted about 1000 bucks (no kidding!) for welding and repainting the tank . So, I guess I made a good deal. Thanks a lot for providing such a great product and also for your excellent service.

Best regards,

Aldo Hoermann
............ Comments from US Customer..........


April 3rd, 2021

Here are a few things that Casewell do not tell you on their website about their fuel tank sealing product:
- Once cured, the stuff is hard like a rock and clear like glass but not so brittle that it will crack if deformed.
- it has almost no smell or nasty fumes at all (a major benefit of you ask me)
- you need to remove fuel and chemical residue from the tank and it must be perfectly dry, but you do not need to go to great lengths to treat or remove rust (a major time saving). It bonds to rust and seals it in.
- you have plenty of working time at room temp, it distributes easily and sticks to the walls of your tank very well to give a very even coating
- when you apply it the material is thick like warm honey, so it will seal up any weeping holes without leaking out of the tank. For larger holes you can cover them with tape from the outside and / or use tank sealing putty prior to sealing. Because the product provides such an effective barrier, you can use general purpose epoxy for this.
- you can use it for all sorts of other applications, including as a very strong adhesive.
- the product is better, and easier to use than any comparable product on the market

The above is based on my observations using the product which I paid for in full. I have no association with the company.

Piers, Western Australia


See below for current MSDS



Average Rating
  • Average Rating 5/5 Stars.
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(5 out of 5 with 2 votes)
Greatest repair product - EVER
  • Rating 5/5 Stars.
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Stephen Tt600 (Wagga Wagga) - June 7th 2021
I have 3 Yamaha TT600's, 83-88, and all have suffered the same fate, split or leaking tanks. Most caused by fuel left idle in the tanks for many years, not my doing. The tanks that explode are only good for stacking on the shelf, the ones that split on the seams or the corners are where this product excels. As mentioned in previous reviews, prepartation is important, but not difficult. Contolling the temperature appeared to be the most critical part of the operation. I just locked the tank in my [...read more]
The only real tank sealer !
  • Rating 5/5 Stars.
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Rob Fry (Perth WA.) - November 3rd 2014
I spray paint bikes for restoration as a side line business.
Have used POR Gold and KBS single pack tank salers before.
The Caswell 2 pack expoy tank sealer is far superior to anything else I've ever used. The instructions are correct and the product is easy to use. Even advice like warming the sealer tins a bucket of warm water in winter is great advice.
Preperation of the tank is essential for best results, the epoxy sealer leaves a thick coating like honey and bonds to [...read more]

Additional Information

Product Data

  • GTS1750