Teflon Tape or Thread Compound for leaking 3/4" pipe fitting?

Discussion in 'Bad Dog Cafe' started by DugT, Jul 11, 2019.

  1. DugT

    DugT Tele-Holic

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    My pipe fitting keeps leaking and it is as tight as I can get it. I used plumbers putty (Edit: I used Pipe Thread Compound) and am wondering if teflon tape would be better. I've used both before and never had a leaking problem before this.

    This is for a new Thermal Expansion Tank that is screwed into a copper fitting. The nut on the copper side is 1 1/4" and the nut on the tank is 1 1/16". I'm using fairly long open ended wrenches and all my strength but it continues to leak slowy which is about a drop every two seconds.

    One option is to take it all apart, clean off the paste and try again with teflon tape. It would be hard to clean all of the paste out of the socket.

    Another option is to find a stronger person or longer wrenches.

    I don't have a lot of experience with plumbing.

    Thanks for any advice.

    Remember, no politics and no fighting! :)

    Edit: Added this photo of the fitting: IMG_20190711_183651.jpg
     
    Last edited: Jul 11, 2019
  2. GuitLoop

    GuitLoop Tele-Meister

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    Picture of the fitting would help answer question. Especially with the nut off so we can see where the connection/compression is happening.
     
  3. RodeoTex

    RodeoTex Poster Extraordinaire

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    That's not really what plumbers putty is for, unless you're talking about pipe dope.
    I'd suggest wrapping it with teflon tape and then putting on pipe dope too.
     
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  4. Shuster

    Shuster Friend of Leo's Silver Supporter

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    Teflon Tape!!
     
  5. rigatele

    rigatele Tele-Afflicted

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    +1 teflon... as for putting dope in your pipe well...
     
  6. Milspec

    Milspec Friend of Leo's

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    Plumbers putty is more about keeping the fitting corrosion-free for easy disassembly down the road than it is about sealing. If this is a compression fitting, you don't want to use either product on it or it will not seal properly....could that be what happened? Remove it, clean the threads well and try it again.

    As they said in military plumbing school....water always wins, just look at the Grand Canyon. So, if there is a pathway, it will always leak.
     
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  7. magicfingers99

    magicfingers99 Tele-Afflicted

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    teflon tape...

    how many wraps? well when I asked the fellow, he told me you wrap it until it stops leaking (ie seals the void).

    don't be stingy with that stuff, it really works..
     
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  8. Chuckster

    Chuckster Tele-Meister

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    Licensed Master Plumber here... 30 years this month.

    Teflon is the choice, but remember, Teflon tape or anything else will not stop or prevent a leak; that is not what it is/was designed for... the threads make the seal. Teflon, Rectorseal, and other applicants are solely to lubricate the threads during the connection process.

    Either your connection is not tight enough, your threads are damaged, the fitting is cracked, or some other situation, but do not rely on Teflon tape to cure your issue. Two to three wraps and torque to seal.
     
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  9. Milspec

    Milspec Friend of Leo's

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    Since this is an expansion tank (should be on the cold supply line right?) it is not a compression fitting. So, clean the threads really well so there are no burrs, wrap with teflon tape (wrap clockwise direction), and install. A little hint here is that you can apply putty over the teflon tape as well, but shouldn't need it to get a good seal.
     
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  10. Chuckster

    Chuckster Tele-Meister

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    Plumbers putty is intended for setting fixtures, such as faucets, drain pop-ups, basin drains, etc. It has no pressurized leak-sealing qualities... just my .02.
     
  11. ce24

    ce24 Poster Extraordinaire

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    Shark bite is great if it's appropriate for your occasion.
     
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  12. DugT

    DugT Tele-Holic

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    Thanks for all of the tips. Here are more details and answsers to questions.
    I didn't use plumbers putty like I said. I used "Pipe Thread Compound TFE Paste"
    It pipe thread compound was used on the previous tank installation by a plumber.
    The tank has the male threads and it tapers from narrower to wider so I would think that means it is a compression fit.

    I attatched a photo of the joint. When I look at the photo it looks to me like it could be cross threaded but it seemed to screw on properly and gradually get tighter as it should. If I do take it apart I will find out if the threads are distroyed but I would think it would be leaking a lot more if it is cross threaded.

    I think Pipe Thread Compound should have worked, Correct me if I'm wrong. It was really hard to get the old tank off so maybe I'm too weak for this sort of job. I'm accustomed to having strong arms from windsurfing and kiteboarding but that ended four years ago and now that I just snow ski and bike, my arms are a lot smaller. Clapton would call them woman arms.

    IMG_20190711_183651.jpg

    View attachment 622487
     

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    Last edited: Jul 11, 2019
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  13. GuitLoop

    GuitLoop Tele-Meister

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    For a connection like that...Remove, clean all threads apply Teflon tape in clockwise direction then crank it back down. Use a wrench with long handle for more leverage if you need to.
     
  14. Milspec

    Milspec Friend of Leo's

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    Maybe it is just the picture, but it looks like it may have cross-threaded
     
  15. RodeoTex

    RodeoTex Poster Extraordinaire

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    If threads are and rusted and or pitted do the Rectorseal AND the teflon.
    Don't make me come up there...
     
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  16. GuitLoop

    GuitLoop Tele-Meister

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    If you count the visible threads on both sides they are the same so I'm guessing NOT crossthreaded but looks like a tiny bit of thread damage from wrench.
     
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  17. Obsessed

    Obsessed Telefied Ad Free Member

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    You've got the right stuff in the pic of pipe compound, but looks like you are not using enough of it. Remove, clean and dry threads and only put the compound on the male threads mostly towards the tip. Reassemble. Keep tightening, but don't back off when you get it tight.

    Long term, you should not connect steel directly to copper, so you should add a bronze coupler inbetween to eliminate galvanic corrosion.
     
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  18. OldDude2

    OldDude2 Tele-Meister

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    I would also suggest that once you get everything cleaned up tighten with your fingers first to make sure you're not cross threading anything.
     
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  19. verb boten

    verb boten Tele-Meister

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    That's the good thing about tape, it actually increases the thread diameter (in a manner of speaking). Go tape!
     
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  20. Erebus

    Erebus TDPRI Member

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    Get your Mapp gas torch out and sweat on some new fittings :)
     
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