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Technical Epoxy That Gasoline Wont Dissolve - Is There Such a Thing

Discussion in 'The Hokey Ass Message Board' started by Oldmics, Jul 15, 2019.

  1. carbking
    Joined: Dec 20, 2008
    Posts: 2,480


    No longer rebuild carbs, but used to do lots of Q-Jets.

    Cannot remember even one where the epoxy on the well plugs was still intact when I disassembled the carb. ALL HAD FAILED!!!!! The epoxy would shrink slightly, and pull away from the edge of the casting. Often, would find the complete blob of epoxy totally separated from the casting in the bottom of the cavity. Rochester offered a foam spacer that would keep pressure on the epoxy, and keep it in place a little longer.

    All of these issues disappeared in 1968 with the revision to the method of sealing the wells to the 1968 and newer Q-Jets. The 1968 and newer don't leak, with or without epoxy. The 1965 ~ 1967 eventually leaked with every epoxy I ever tried, including JB Weld, and every other similar product available at the FLAPS.

    The solution to the leakage on the earlier Q-Jets was to remove the pressed-in plugs, and carefully thread the casting for screw-in plugs. There is a learning curve to prevent splitting the housing. Suggest NOT trying this on an extremely rare/expensive carburetor as your first attempt. Learn on junk before doing it for real.

    To the OP - I don't have an answer to what epoxy will work, I never found one; but if a 1968 or newer, don't even bother, it isn't necessary.

    lothiandon1940 likes this.
  2. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,967


    If you are sealing and not trying to build a machinable place get gas tank seal like used by the desert racers (think motorcycles here). Any good tank seal is going to have to be gas proof not gas resistant. You could paint it on with a brush.

    I used to use some stuff that I bought at the dirt bike shops called "Tank Seal" on my bikes when I discovered a hole in an already painted tank. That stuff would seal up pinholes up to 1/8" dia.
  3. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,967


  4. '51 Norm
    Joined: Dec 6, 2010
    Posts: 647

    '51 Norm
    from colorado

    I once had an old Rambler that had about a zillion rust pinholes in the bottom of the gas tank. I kept a bar of soap under the seat and every week or so I would scrape it all over the bottom of the gas tank. It would remind me that it needed another coat by leaking.
    Irish Spring was my preferred soap since it smelled so nice under the seat.
    lothiandon1940 and Truck64 like this.

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