Plastic gas tanks are commonly found on lawnmowers, quads, motorcycles, and cars. These items are popular for their strength and can be easily replaced if damaged. However, if a plastic fuel tank has small holes or tears, there is a fairly easy way to repair them. Use epoxy putty and a small sheet of fiberglass to seal the opening. If you are experienced in welding, you can use a plastic welder to seal the crack. Before fixing the plastic tank, be sure to drain it and clean it completely with a cloth and vinegar. You should always wear safety glasses, gloves, and a dust mask when working with toxic fumes.
Method 1 of 3: Drain and Clean the Tank
Step 1. Drain the tank into a gasoline-proof container for temporary storage
Place a container under the tank opening. The container must be safe for storing gasoline (for example, a gasoline jug, jug, or sturdy canister). If you are storing gasoline in a container with a smaller lid or opening, you should place a funnel inside the container opening before pouring in the gasoline. Open the cap on the tank and let the gasoline drain into the container. Then leave it in a safe area.
You should look for the words "oil," "gasoline," or "fuel" on the side of any gasoline-proof container
If you use an unauthorized container, you could accidentally expose the gasoline to a contaminant that will end up damaging your engine in the future. Additionally, unauthorized containers may become more likely to contain an electrical charge. You run the risk of an explosion or fire if you store gasoline in an unauthorized container and handle it improperly.
Step 2. Let the tank dry a bit and clean it
If possible, you should clean the inside of the tank with a clean cloth or towel. Wipe the outside with another clean cloth or towel. If it's hot, you can leave the tank in the sun with the opening facing up for 3-4 hours. If it's not hot, you can let it air dry for at least 6 hours. Clean it again after it dries to remove most of the gasoline residue.
- If you're using epoxy putty to patch a hole, you really don't need to remove all the gasoline residue.
- You may not be able to reach inside the tank to clean it. It's okay if you can't, just let it dry a bit more.
Step 3. Fill the tank with white vinegar and let it sit overnight if you are soldering it
If you're welding the crack or hole, it's a good idea to clean the tank a little more thoroughly. Place a piece of tape over the crack or hole or fill it in with a small screw to temporarily close the gap. Fill the tank with white vinegar to the brim. Let it sit overnight to allow the remaining gasoline particles to erode.
- If you want, you can use laundry detergent and hot water instead of vinegar.
- After letting it sit overnight, you should empty the tank and rinse it with water. You can add 4-5 tablespoons of baking soda before rinsing it off if it still smells like gasoline.
- This is the main reason why epoxy putty is considered the preferred method of sealing a plastic tank, as it requires less cleaning beforehand and is not as dangerous as it does not involve heat.
Step 4. Let the tank air dry again after washing it with water
You should let the tank sit in the sun for another 3-4 hours. If it's not sunny, you should let it air dry in a well-ventilated area for at least 6 hours. Wipe the tank again with a dry cloth to remove all debris or water.
Step 5. Clean the accessories that are attached to the tank while you are away
If you've already removed the gas tank, this is the perfect time to clean the area where the tank meets the mower, car, or engine. Disconnect the electricity from your device and then get a clean cloth. Clean the fittings, pipes, or threads where the tank connects to the device.
- Friction can cause cracks or seams to separate, so cleaning the area around the tank keeps it safe in the future.
- Dampen a cloth with rubbing alcohol to clean particularly dirty areas.
Method 2 of 3: Use Epoxy Putty
Step 1. Clean the unsealed area with rubbing alcohol
Take a cloth and pour some rubbing alcohol on it. Squeeze the towel so that the entire fabric is moistened. Gently and gently rub the section where the crack, hole, or leak is located. You should dry any particularly sensitive sections. Rub at least 1 to 2 inches (2.5 to 5.1 cm) around the opening in all directions.
Isopropyl alcohol removes any dirt or grime that can erode the epoxy putty over time
This is the preferred method of sealing a plastic gas tank, as it does not involve heat. In addition, it is much simpler and cheaper than the other methods.
Step 2. Knead the 2-part epoxy putty to activate it
You can only seal a tank with 2-part epoxy putty that is labeled "plastic putty" or "multipurpose." Put on a pair of rubber gloves and unwrap the putty. Rub it between both hands and apply pressure. Separate it and rub it again. Then mix the 2 parts of putty until it turns a solid color.
Make sure the epoxy putty you use is suitable for plastic tanks. If you use another caulk designed for metal or wood, the tank will continue to leak gasoline when you fill it up
Step 3. Apply a portion of the caulk around the edges of the crack or hole
Remove a dollop of caulk and press it around the edges of the crack, hole, or leak. The two-part epoxy putty has the consistency of clay, so you can separate the pieces and spread them out. Spread it over the tank and apply pressure with your fingertips to distribute it. Press it into the plastic so that it is thinner than 1/4 inch (6 mm).
The epoxy putty should be nearly flat. If it settles in thick globs around the crack or hole, you will have trouble getting a tight seal
Step 4. Place a small sheet of fiberglass cloth on top of the epoxy putty and apply pressure
Get a small strip of fiberglass cloth and cut it to fit over the epoxy putty. Allow the fiberglass to extend at least 1 inch (2.5 cm) beyond the edge of the epoxy putty that you apply to the hole or crack. Lay the fiberglass on top of the putty and apply firm pressure to permanently set it above the crack.
- You should wear thick gloves, safety glasses, and a respirator to cut the fiberglass.
- You can also cut some fiberglass from a larger sheet with a straight edge utility knife and use it in place of the fabric.
- Press down hard to make sure you remove any air bubbles in the epoxy putty.
Step 5. Spread the rest of the epoxy putty over the joints where the fiberglass meets the tank
Use the rest of the caulk to cover the area where the fiberglass meets the plastic tank. Spread it out as you did before by removing the individual pieces and applying pressure. You should cover at least 1 inch (2.5 cm) in both directions where each joint meets to close the crack. then press down on the epoxy putty to flatten it out.
There cannot be openings where the tank and fiberglass meet. Cover the entire joint with caulk
Step 6. Allow the area to dry and sand it by hand to remove excess caulk
Wait 4 to 5 hours for the epoxy putty to set completely. Wear a pair of thick gloves, a dust mask, and safety glasses. Next, take a sheet of 100-grit sandpaper and hand rub the area you patched. You should rub lightly until the caulk, fiberglass, and extra layer of caulk are almost flush with the plastic in the tank.
You can use standard spray paint on the area you patched if you want to blend in with the rest of the tank
Method 3 of 3: Welding the Plastic to Seal
Step 1. Buy or rent a plastic welder
This tool is used to fill holes in plastic using heat to melt another piece of plastic over the opening. The soldering iron you use will depend on the type and thickness of the plastic. Take the tank to a local hardware store and ask which rods work best for your tank.
Although you can use any type of plastic welder, the time it takes and the difficulty of the task is greatly reduced by using a welder with the appropriate size rods
Step 2. Put on a welding helmet, heavy gloves, and a dust mask
Welding generates a lot of heat and noxious fumes when operating. Protect yourself by wearing a welding helmet, thick gloves, and a dust mask or respirator over your nose and mouth.
Wear a respirator instead of a dust mask if you have one. However, a respirator is not necessary
you can solder the gap on the plastic if you prefer. To carry out the welding, you must first apply the plastic to the area and then heat it. This method is not preferred as it is more likely to start a gas tank fire. You should only weld the tank if you have experience welding plastic and have thoroughly cleaned the tank.
Step 3. Place the dry tank in a safe place, preferably outdoors
Welding produces a lot of fumes, so you should work in a well-ventilated area. The best option is to work outdoors if you have an outdoor space. Make sure there are no flammable items within 10 feet of the area you are working in.
Step 4. Turn on the soldering iron and prepare the rod for soldering
Plug and flip the switch to turn on the soldering iron. Adjust the temperature on the digital reader and prepare the plastic rod. Hold the rod at the edge of the crack or hole with your non-dominant hand and position the tip of the soldering iron before pulling the trigger to begin melting it.
The temperature at which you set the soldering iron will depend on the type of plastic you have. Thick plastics require higher temperatures, while thin plastics require less heat. The tank is most likely made of acrylic, polyethylene, or polyamide, so start at 350 ° C (660 ° F) and work your way up from there
Step 5. Start welding from the outside of the hole or crack
Turn on the soldering iron to melt the plastic rod directly to the edge of the crack. As soon as the rod melts over one area, you should press it down a bit and slide it into the next section. Hold the tip of the soldering iron 1 to 2 inches (2.5 to 5.1 cm) from the surface of the plastic tank where the wand is located. You should move slowly around the edge of the crack, leak, or hole. Work in one direction and cover the edge twice if you don't see the solder fusing into the plastic.
- You may have to cover your strokes several times so that the solder material will fuse with the plastic.
- It should look like you are adding thick liquid to the plastic tank.
- Increase the temperature setting on the soldering iron if you are not melting the soldering rod.
- If the crack or leak is really thin, you can weld directly on it instead of working from the outside to the inside. However, the crack must be really small. Anything wider than ½ cm (¼ inch) requires work from the outside to the inside.
Step 6. Work your way into the center of the opening to cover the hole
Once you've covered the outside edge of the crack, hole, or opening, you should begin working your way inward by placing the dowel over the areas that you've already covered. Continue to hold the rod 1 to 2 inches (2.5 to 5.1 cm) from the surface of the plastic tank and work your way toward the center of the hole. Keep doing this until the opening is completely covered.
You can always go back and cover an outside section if the solder doesn't bond the first time
Step 7. Wait at least 8 hours to let it settle completely
Set the tank aside for at least 8 hours until the solder material cools and dries. Once you've waited, you should check the tank to make sure you cover the opening completely.
If you missed any section of the hole or crack, you should repeat the process to cover that area. Wait another 5-6 hours and check the tank again
Step 8. Sand the surface smooth with 100-grit sandpaper
Once you confirm that the solder is completely covering the hole and has cooled, you can sand it down. Get a sheet of 100-grit sandpaper and rub the area you've welded. Lightly rub the entire section back and forth until the solder is almost flush with the rest of the tank.
- You can spray paint the plastic tank if you want to cover up the welding job.
- Solder material will become sharp and jagged over time if you don't sand it down.
- Never use a soldering iron or soldering tool near an open flame.
- You should always protect your eyes, hands, and lungs when working with harmful fumes.
- You should work outdoors to make cleaning easier and avoid trapping vapors within the workspace.