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OT: Plastic Gas Tanks ???

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  • OT: Plastic Gas Tanks ???

    I have an old outboard motor and several small engines that have plastic gas tanks that are cracked and leak. I have tried JB weld to no avail. Has anyone found a way to seal up plastic gas tanks so they stop leaking?

    TIA
    Randy
    Do yourself a favor and see if your TV carrier has America One News Network (AONN). 208 on Uverse. It is good old fashion news, unlike the networks, with no hype, bias or other BS.

  • #2
    They are made from polypropylene. You can "weld" it with some scrap material and a soldering iron.
    Free software for calculating bolt circles and similar: Click Here

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    • #3
      The only sealer i know thats gas resistant is called Seal All in a yellow squeeze tube.

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      • #4
        Just about nothing will stick to polyprop. Heat welding is about the only way to fix it. It the tanks are old enough that they are cracking welding probably won't work either. If the cracks are from mounting stress and vibration then it may work.
        Free software for calculating bolt circles and similar: Click Here

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        • #5
          Originally posted by Evan View Post
          Just about nothing will stick to polyprop. Heat welding is about the only way to fix it. It the tanks are old enough that they are cracking welding probably won't work either. If the cracks are from mounting stress and vibration then it may work.
          not strictly true.... but close enough for most purposes. There are polyurethane glues that will stick successfully to polyprop. 3M do them but they are expensive. With very good surface prep you can get epoxies to stick them.
          something mucky and old containing a solvent (petrol) is going to be a real challenge.to anything...

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          • #6
            Originally posted by ogre View Post
            The only sealer i know thats gas resistant is called Seal All in a yellow squeeze tube.
            I tried the Seal All to repair a plastic fuel pump. It was a monumental failure, even though I let it cure for a week or so before use.
            Lynn (Huntsville, AL)

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            • #7
              Clean and sand exterior of tank.
              Wedge open cracks using appropriately sized music wire.
              Apply generous coating of "Gorilla Glue" about 1 inch wide centered on crack location.
              Take appropriately cut strips of fibreglass cloth (leave about 4 inches at ends to allow for taping - use mylar packing tape applied along and across the strip at the ends).
              Wet the fibreglass strips with water and apply, maintaining as much pressure as possible.

              It may take several layers of glue and fibreglass to attain sufficient strength.

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              • #8
                Well, we all better get ready to fix polypropylene fuel tanks.... Thieves nowadays don't siphon the fuel from the vehicle anymore - they puncture the tank instead!

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                • #9
                  No need to get all fancy with glues that probably won't hold. It's easy to heat weld. Practice on a scrap first.
                  Free software for calculating bolt circles and similar: Click Here

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                  • #10
                    Harbor Freight has several plastic welders, see:

                    http://www.harborfreight.com/catalog...plastic%20weld

                    I think the first, most expensive item is essentially a tiny, concentrated hot air gun, not just a simple soldering iron type of thing. Dunno about its effectiveness, but there it is.

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                    • #11
                      What kind of outboard and about what year? Depending on the answer you might get a decent NOS replacement, or a reasonable remanufactured lookalike.

                      Finest regards,

                      doug

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                      • #12
                        It is a 3.5 hp Nissan 2 stroke of @1993 vintage.
                        It looks like I am headed to HF for a plastic welder. I was hoping that there was some sort of liquid coating I could slosh around that would fill up the cracks. Or better yet a version of that spray they advertise on TV that seals up a screen door ;^)

                        Thanks for the replies Guys

                        Randy
                        Do yourself a favor and see if your TV carrier has America One News Network (AONN). 208 on Uverse. It is good old fashion news, unlike the networks, with no hype, bias or other BS.

                        Comment

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