Teflon tape for gasoline applications?

Discussion in 'The Garage' started by Powershouse, Jul 31, 2008.

  1. Powershouse

    Powershouse Flower Sniffer Supporter

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    I mounted a new gas tank the other day and when I put gas in it the gas ran out around the bolts that hold the petcock in place. Somewhere along the way I picked up the notion that there is a special type of teflon thread tape for applications that involve gasoline. When I checked at the auto parts store the guy behind the counter looked at me as if I'd asked for a left-handed wind shifter.

    Will plain old teflon thread tape work for petcock bolts on a fuel tank?
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  2. Yad

    Yad yet another dave

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    I think the tape will hold up, but from your description that's not what you want. Maybe I don't understand - bolts, plural, that hold the petcock in place? I think you want some sort of o-ring for each, or a gasket that covers the whole petcock base. Teflon tape is just for filling in very small gaps in hose threads.
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  3. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    You are not supposed to use teflon tape with gasoline applications, supposedly it dissolves.

    However, it sounds like you want a sealant like permatex pli-a-seal or something. You can always bring your tank into the local parts store and ask for a suggestion, or post up a pic or two here so we can see what you are dealing with.
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  4. threadkiller

    threadkiller Long timer

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    Teflon tape is not designed to seal a threaded joint. It's designed to reduce friction so the threads can be torqued enough to seal. So to that end, I don't see why it wouldn't work with any threaded joint (within reason).
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  5. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    Pipe joints have a taper to them. Regular bolts have parallel sides so they never draw up against each other in the same way.
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  6. xymotic

    xymotic Long timer

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    There is special Teflon tape for petroleum. It's used mainly for natural gas, it's thicker than normal Teflon tape. Available at home depot or whatever, just ask for yellow teflon tape
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  7. datchew

    datchew Don't buy from Brad

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    +1 It's for hydraulics and other petrol-based applications.

    Airhead petcocks are famous for leaking. The white standard teflon tape won't work. The yellow stuff will.

    It's been gasoline proof on my airhead for well over a year.
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  8. kubiak

    kubiak Long timer

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    i use the yellow tape too and it doesnt leak so far.its been on my tank threads for about 2 years so far.
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  9. minnjim

    minnjim Been here awhile

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    Many major manufacturers of hydraulic equipment recommend NOT using Teflon tape, as it often leaks and bits of it break loose, then fouling valves and other components. Loctite PST Pipe Sealant is highly recommended and IMHO the way to go. I've seen pipes doped with it, then tightened only hand tight that held 100 psi. No, I'm not a Loctite rep, just a satisfied user. I rarely use tape anymore.
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  10. G-Force Junkie

    G-Force Junkie Long timer

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    I agree. At work we rig boats, including all the fuel, hydraulic, oil and water systems. We only use Loctite 567 PST with teflon on everything. It is amazing stuff, works on anything, and also works well as an anti-seize paste, expecialy on stainless hardware.
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  11. Uncle Ernie

    Uncle Ernie Long timer

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    Crap. It will be fun to see how long my Teflon tape holds...
    So where do you get this Loctite- auto parts store?
    (never seen it before)
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  12. ADV8

    ADV8 Long timer

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    No O-Ring ?.
    What normally seals it from the factory ?.
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  13. Pro_Marinero

    Pro_Marinero Carbon Sasquatch

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    I used Permatex Aviation Sealant to seal the drain bolt on my old GL1000 fuel tank. This was insisted upon as the only way to seal it by the foremost GL carb guru in the USA on his site. Surprisingly, I found this quite readily at my local auto parts store.
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  14. mjydrafter

    mjydrafter evil boy for life

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  15. C Squared

    C Squared Now with TURBO! Supporter

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    Yup, you want a Permatex thread Sealant.
    Great stuff and a "tail" of it never finds its way into your carb. etc.

    If your NAPA or CarQuest does not have it on the shelf...

    They really should! They can get it.

    Also, most good bearing supply places have it.
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  16. rufus

    rufus We're burning daylight...

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    That won't stop your leak. The bolts shouln't be sticking up into the gas. There should be either an o-ring or a gasket that seals it. Is it an aftermarket plastic tank? About 1/2 of the tanks i have bought were not flat at the o-ring/gasket surface. Take a flat razor blade and scrape it across the surface at a 90 dergree angle. This will slowly peel away the material until you get it flat. Sometimes the sealing surface is recessed. Just break a blade to the needed length and grab it with some vise grips.
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  17. weldaveweld

    weldaveweld twowheeltexan

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    Your regular thread tape will work for liquid petroleum. Don't go crazy with it ...2-3 rounds will suffice nicely.You may also want to put a film of teflon sealant on the threads prior to applying the tape.
    If you wonder how I know
    I have been an independent contractor who has worked solely on fuel /piping systems big and small for almost 30 yrs.
    If its stainless there is a thread tape made with nickel.
    good luck
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  18. underkill

    underkill Horsepower Junkie

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    I used the regular white teflon tape on the fuel system on my car... at first... and then it started to disintegrate. I couldn't even FIND where the tape went, it was just gone... :huh I then switched to the yellow tape and haven't had any problems since, but I wish I'd known about that pipe sealant stuff. That looks like the best way to go.
    #18
  19. rxlamont

    rxlamont Adventurer

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    Permatex Aviation Sealant. Gotta go to NAPA to get it; in Chico CA, it wasn't at Pep Boys, Auto Zone, Reilly's, or Kragen.

    FWIW

    LaMont
    #19
  20. H96669

    H96669 A proud pragmatist.

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    Just because I need some of that, I was checking specs this morning:

    http://www.loctite.sg/sea/content_data/93780_577EN.pdf

    Loctite 577 Thread sealer, 100% resistance to unleaded fuel....slightly better than the 567 which is 80-90% after xxx hours. Also 577 is much better on Ethanol/Acetone resistance than the 567.

    http://www.sjgogo.com/pdf/567-en.pdf

    I don't see that "Fuel resistance" in any of the Permatex products but for the Aviation stuff and that one can be a real PITA to remove later.Unless you know of course that it is a Shellac and cleanable with Alcool....but then that would bring some concerns as to the Ethanol in most of the US Fuel eventually eating it.:D

    And...if you want to find them Loctite products, Grainger or Acklands-Grainger for us Canadians usually has them. Just get ready to pay.....the best ain't cheap.
    #20