• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

Teflon Tape?

Discussion in 'Compressors, Boosters and Blending Systems' started by Isaac-1, Jul 18, 2008.

  1. Isaac-1

    Isaac-1 Instructor, Scuba

    320
    0
    0
    Which type/grade of teflon tape do you recommend for high pressure air applications when using NPT fittings, etc? I ask because I ordered some fittings and valves from one of the online suppliers that specializes in selling these type things for scuba compressor use, I also ordered some teflon tape from this supplier (not knowing where any of the rolls I had previously bought had disappeared to), the teflon tape that arrived was standard "commercial grade" white teflon tape, the fine print said it was rated to 150 psi. In other applications (pre built whips, etc) I have seen both white and heavier yellow (gas grade?) teflon tape used.

    thanks Ike
     
  2. CraigAClark

    CraigAClark Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: South Florida
    519
    21
    18
    I have been using the tape available from my local Swage-Lok distributor for most gas applications, for well over 20 years. It seems to be twice as thick as the stuff you get at the local hardware store. I also use a gas specific tape for oxygen. On both, I put a small dab of O2 compatible grease to help things along. Especially for stainless and monel 400.

    Craig
     
  3. pescador775

    pescador775 Loggerhead Turtle

    2,652
    2
    0
    Isaac, the subject of tape is simple except when it's not. I never heard of tape with a psi rating. Learned something new. When sinking large valves into iffy thread I use a thick tape. Actually, an NPT valve is supposed to seal with one to three exposed threads but on old, vintage equipment this may only be possible using thick tape. When joining stainless I use thin tape, particularly when the thread size is 1/4 inch NPT, NGT or smaller. There are certain delicate connections such as sinking a stainless, 1/8 inch NPT into an aluminum or brass block. I use teflon paste in these applications and moderate torque. This type of joint is so effective that the sealed parts can be rotated slightly to make the connection align without breaking seal. Also, if a stainless to stainless fit is rough, cranky and won't seal, the paste will make it seal most of the time. If that doesn't work there is something wrong with the thread and may need chasing with a tap or die. The product which I use are white in color and may or may not be oxygen rated, especially paste. However, I see no reason that teflon tape cannot be used in oxygen.

    Edit: I schlepped out to the diving locker to verify what I am using to seal joints. The tapes are "MIL SPEC" and the paste is Fluoramics Formula 8, 10,000 psi, oxygen safe.
    http://www.rtmagazine.com/issues/articles/2006-04_35.asp

    Formula 8 and LOX 8 (submersible systems) are available from McMaster Carr. LOX 8 is cat no. 4538K6 and formula 8 is 4538K1
     
    Last edited: Jul 18, 2008
  4. captain

    captain Captain

    6,733
    3,253
    113
    I witched from teflon tape to Permatex Thread Sealent with Teflon. It is rated to 3000psi and as Pescador says it allows rotation for alignment. It also seals leaks that won't seal with teflon tape. Only down side is it is not for oxygen service.
     
  5. Doc Harry

    Doc Harry Solo Diver

    # of Dives: 500 - 999
    Location: Appalachia
    3,311
    553
    113
    Ace Hardware sells MIL SPEC T27730A teflon tape for about $2 that is adequate for oxygen service.

    Good enough for O2 clean plumbing, good enough for air!
     
  6. Hoosier

    Hoosier Solo Diver

    5,974
    5
    0
    OMG... I have never considered and heard about a rated Teflon tape. I am also using the standard Teflon tape (white) from the local HW stores. I saw that there is twice thick tape for an gas application (as I recall, it is yellow). I am simply putting more tape on the threads. I am regularly checking a leak with a soapy water. So far so good..

    Based on my experience, the check and Priority valves are more leaking points than the Teflon tape in itself.

    For a commercial base, I can see the point, but for an individual base..... I think it is overkill..

    Guys... Make sure your hands are O2 cleaned as well... ;)

    Just my 2 bar.
     

Share This Page