Welding plastic Toro fuel tank


Old 05-05-17, 10:04 AM
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Welding plastic Toro fuel tank

I have a 1981 Toro 30900 line trimmer with a kioritz engine on it that has a leaking fuel tank. I cannot get a factory replacement for it, and some locktite plactic repair in at tube holds it for awhile, but it eventually cracks open again with the vibration. I thoughjt of buying a plastic welder, but I could buy a new trimmer for the cost of one of those. My welding ace said he has never had a call to do it, so he doesnt have one either. I thought I had seen a tape that you could apply to a leak like this, and then soak it in a fluid that comes with the tape that might work, but I have not seen it anywere around here. the fuel is leaking from a seam that goes completely around the tank, like it was put together when manufacutured buy putting the two halves of the tank together there. Any I deas for quickly repairing this tank?
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Old 05-05-17, 10:15 AM
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I have an ultrasonic welder but I've noticed it's not terribly effective on older brittle plastics.
That tank probably isn't plastic anyway..... more like polypropylene.

I've used two part epoxies with fairly good results but it's important that the tank be clean and free of grease, oil and gas residue.
Old 05-05-17, 10:27 AM
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Depending on the type of plastic, I have had some luck with using a soldering iron or pencil (electric, not open flame!) to melt and seal small areas. Often I will use a small piece of aluminum window screen as a reinforcement, using the hot iron to press it into the plastic over the repair. Impossible to do a neat job, but for something like this that's not so important.

Worth a try as a last resort.
Old 05-05-17, 01:02 PM
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Finding out what plastic the tank is would help. There are hand pens/wands for 3D printers that are pretty inexpensive that might work if the plastics are compatible.
Old 05-05-17, 04:55 PM
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We have several different types of plastic welders at work and to be honest nobody really uses them anymore because they simply dont work.

Occasionally they might get a decent "weld" but the application is nothing like trying to seal something like a gas tank.
Old 05-05-17, 05:45 PM
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Is it that the seam is opening up a lengthy split . . . . or is it just a hole that refuses to seal ?

If it's small enough, I'd consider drilling a hole in the center of the split and placing fender washers to reinforce both the inside and outside with a screw head inside and with the nut on the outside . . . . maybe supplemented with another effort of Loctite's Plastic Bonding System, or some GB Weld.
Old 05-05-17, 06:44 PM
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Old 05-07-17, 08:22 PM
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Toro line trimmer fuel tank leak

I have a 1981 Toro 30900 gas trimmer with a leaking fuel tank that I can't get a replacement for. I see that Permatex makes a fuel tank repair kit for plastic, but since this is an opague white tank that you can see thru, that it might be polymer rather than plastic. Is there a kit you guys are familiar with that might work on poly, or how to tell if it is plastic or?
Old 05-08-17, 09:19 AM
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I have used a wood burning tool for crafts, it looks the same as a pencil soldering iron. I used strips cut from paint can lids and string trimmer line for welding rods, start outside the crack in a circular motion and begin to create your pool and introduce some of your welding rod, slowly move your pool along the crack until you have completed the repair, it is a slow process but effective for me. Have a good one. Geo
Old 05-12-17, 08:56 AM
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Welding plastic fuel tank

I went looking for the "rescue tape" and in my search, I found that JB Weld makes a product for gluing poly tanks among other things. It is a Plastic Bonder Syringe, (two part epoxy) Item # 39F870 available from Graingers Supply. They had it shipped to my store here in Ohio and I got it next day freight free. It has cured and is holding the fuel in the tank, but I have not run it yet to see if the fix shakes loose. I will let you know. Thanks for all the tips!
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