Leaking fuel tank

[kburns]

Troy Bilt TB25ET string trimmer. No UT #, the sticker is gone. On the side of the engine is a family # 3MTDS.0314RA:EM.

The fuel tank on this trimmer is above the engine, and the fuel lines feed out the bottom of the tank. The tank is leaking along the seam where it was glued or heat welded together during assembly. I guess the tank is HD polyethylene or propylene. What would be a good glue or sealer to use on it? Should I try to seal it up with my soldering gun? Suggestions would be appreciated.

Ken

[KE4AVB]

Ken won't be a UT number as the model number all start with 41 for the series and were only five different versions.

The fuel tank on this trimmer is above the engine, and the fuel lines feed out the bottom of the tank. The tank is leaking along the seam where it was glued or heat welded together during assembly. I guess the tank is HD polyethylene or propylene. What would be a good glue or sealer to use on it? Should I try to seal it up with my soldering gun? Suggestions would be appreciated.

Preferable method is just replace it.

If you wish to try be extremely carefully and do it outdoors. It is probably the HDPE plastic. Empty and wash the tank to remove all trace of fuel and oil. Heat weld the seam; have extra plastic of the same type to refill and smooth the joint. Use no more heat than absolutely necessary as the plastic will become damage or burn if heated too much. It also can be burning without any signs of a flame.

As for glue there is little if any that works on HDPE. It one of the plastics that nothing in glue line seems to works on.

[bobodu]

I have used a soldering gun with success. Also, if I can determine what type of plastic is used, I have an assortment of plastic welding sticks from Harbor Freight that I grind up in a crank pencil sharpener. Then I use a suitable solvent to make a patch paste.....I do not like repairing plastic tanks though, but at least you can throw a string trimmer if it catches fire.

[KE4AVB]

That why you go as deep as you can when welding these seams. You are wanting it to fused as it were one solid piece. It does help to have a variable temperature soldering setup so you can control the melting temperature. Also depending how large an area your working with you may need work in stages as not create more problems with melt out. When working with fuel tanks you can't halfway do the job. It better to take your time than spend time recovering from sever burns later or worse.

There one other problem can show up especially with older tanks and it is UV damaged plastic. When damage by UV there will a layer of heavily degraded plastic would need to be removed in the area of the weld; of course, you would replace this removed material during the welding.

Bob I haven't seen a solvent based product that will dissolve HDPE yet and one the reasons they are using for fuel tanks and chemical storage.

[HondaG100]

Take it from someone who has years of plastic welding experience. I have welded many fuel and water tanks with professional equipment and even then it is not easy to get a perfect seal. It usually takes several attempts to get it to hold pressure. Do not ever use anything to repair an HDPE tank except HDPE. Nothing else will bond correctly. Clean with alcohol or similar solution and lightly sand the surface before you weld to get rid of the natural oils in plastic. For a small hole you can sometimes do the trick with only a heated up screwdriver tip. New tank is best though as mentioned.

[Deere2me]

Troy Bilt TB25ET string trimmer. No UT #, the sticker is gone. On the side of the engine is a family # 3MTDS.0314RA:EM.

The fuel tank on this trimmer is above the engine, and the fuel lines feed out the bottom of the tank. The tank is leaking along the seam where it was glued or heat welded together during assembly. I guess the tank is HD polyethylene or propylene. What would be a good glue or sealer to use on it? Should I try to seal it up with my soldering gun? Suggestions would be appreciated.

Ken

You can try the ol' soldering iron trick. Personally, I use a thin ( not so viscous)two part epoxy called Epoxo 88. Clean the area with carb spray, rough it up with sandpaper and spread the goop on it. Any two part should work. It won't last forever, but then just pop the patch off and repeat.
You can also try some chit called Seal All, it works for a while also. http://eclecticproducts.com/sealall.htm

[kburns]

Thanks for the suggestions. I'm going to give it a try tomorrow & will let you know how I do.

Ken

[Matt]

i kept a lawnboy mower goin for a couple of years with seal all on the tank. temp/cheap fix for sure but thats all i was wantin. how long you plannin on keepin the trimmer?