There is some polyethylene glue called gorilla glue that is available in hardware stores around here that worked on some water tanks i have where nothing else would stick for very long. Great care must be taken not to blow yourself up working on gas tanks. How To Replace An Rv Roof Vent Cover Roof Vent Covers Vent Covers Roof Vents How to repair a black plastic lawn mower gas tank. Will gorilla glue work on plastic gas tank . The gasoline will attack the product. Gorilla glue (aka urethane) might not be compatible with gasoline. I tried goop adhesive but petrol ate through it. Don't have the bottle anymore to check for applications but it does stick to poly tanks like nobodies business. There is no effective patching compound other than welding on a piece of metal or plastic as dependent upon the original construction of the tank. I use “scotchbrite” or sandpaper soaked in 90 weight gear oi. Depends upon the plastic and how clean you get it before gluing it. U...