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Drilling into a fuel tank

Discussion in 'Technical Discussion' started by Trak, Aug 28, 2018.

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  1. Trak, Aug 28, 2018
    #1
    Trak

    Trak Member

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    I want to add fuel tank level monitoring system. I plan on using Maretron fluid pressure monitors.

    I have fiberglass fuel tanks about half full of diesel. If I cannot find an existing inspection plate to use, I will need to drill a hole in the top of the tank. Can this be done with fuel in the tank safely?
  2. Pascal, Aug 28, 2018
    #2
    Pascal

    Pascal Senior Member

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    Yes, we did that recently to tap a genset return in a plate. The key, whether drilling into metal or fiberglass is run a shop vac to suck debris out
  3. Oscarvan, Sep 27, 2018
    #3
    Oscarvan

    Oscarvan Senior Member

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    Still a chance of some pieces dropping down no? Guess they'd be stopped by the first filter they get to....
  4. Capt Ralph, Sep 27, 2018
    #4
    Capt Ralph

    Capt Ralph Senior Member

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    Do not punch thru, let the bit work. Medium to fast, very light pressure. As Pascal said, Shop vac hose rite next to the bit.
    Hole saw, the same plan. 1 or 2 degrees off angle, when the hole saw starts to cut thru stop, grab the doh-nut and hand cut the last fibers with a knife.
    If the doh-nut falls in, I don't think its a big deal, May help to keep the bottom of the tank clean.

    Use epoxy suitable for fuel exposures or a tank flange with fuel proof gaskets and inner ring.
    Do not use self tapping screws in a glass tank as you could in an alloy tank.
  5. Fishtigua, Sep 28, 2018
    #5
    Fishtigua

    Fishtigua Senior Member

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  6. Pascal, Sep 28, 2018
    #6
    Pascal

    Pascal Senior Member

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    I ve used the Gobius on a holding tank but How do you install that on keel tanks ?
  7. Jdow, Sep 29, 2018
    #7
    Jdow

    Jdow New Member

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    Not sure if it actually helps but I put one shop vac blowing into the fuel fill, and one next to the hole saw sucking up the dust. I do not cover the vent. Don’t believe it makes even 1 psi in the tank but some air does blow out when the drill goes through.
  8. GhostriderIII, Oct 8, 2018
    #8
    GhostriderIII

    GhostriderIII Senior Member

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  9. Trak, Oct 8, 2018
    #9
    Trak

    Trak Member

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    I have fiberglass tanks that are glassed in between stringers. Only have access to tops of tanks. It may work on my blackwater tank.