Leaking NPT threaded connection help

Discussion in 'Equipment' started by kinetic, Oct 17, 2017.

  1. kinetic

    kinetic Webmaster

    I got a 55g water tank (Ace Roto: https://www.ruralking.com/ace-roto-mold-55-gallon-vertical-dome-top-vt0055-20.html) to hold RO/DI water. It came with a bulkhead with a threaded Female NPT.

    I went to Home Depot and got a male NPT to slip converter, and put on a spare union ballhead that I had laying around.

    Unfortunately, I have a super slow leak from the threads between bulkhead and the MPT > Slip fitting. It drips probably once every 10 minutes or so. I actually stood there for 10 minutes and didn't see much happen, but I think a new drop of water came off of it, who knows. There's a constant wet spot and I can see a small bit of water collect on the plumbing.

    I threaded it as far in as I could. I tried using some plumbers tape, but that didn't work either. Any ideas?

    Things I'm thinking of trying
    1. Use plumber cement (is this safe?)
    2. Use silicon on the threads and rethread it in
    3. Replacing the bulkhead with a slip bulkhead instead of threaded (somehow, not sure how I can get my hand all the way into this tank to put it together)

    Any other ideas?



  2. Coral reefer

    Coral reefer President

    You use some teflon tape? 3 layers?
    I often use "liquid teflon" from hardware store.
  3. rygh

    rygh Supporting Member

    I use silicone on all threaded connections.
    Seals great, and you can take them apart easier.
    Let it dry overnight before getting wet.
    Don't use it if there is a chance you may partially unscrew it. Doing that rips it apart, and you can get a leak.
  4. kinetic

    kinetic Webmaster

    I always assumed teflon was for metal threaded fittings? I've used them on PVC before, and people thought I was weird. I have a ton of it left, so maybe I'll try that!

    OK that's good to know. I'll try this next if the 3 layers of teflon tape doesn't work.

    Last question: is it common for NPT threads like this to leak without silicon/teflon?
  5. sfsuphysics

    sfsuphysics Supporting Member

    Yeah, plumbers paste instead of tape
    kinetic likes this.
  6. Yippee

    Yippee Supporting Member

    I am using Rectorseal T Plus 2. For metal and plastic pipe threads.
    kinetic likes this.
  7. xcaret

    xcaret Supporting Member

    What both Mikes suggest, just make sure is the safe for drinking water or teflon tape. Do not over tighten or you may break the bulkhead.
    kinetic likes this.
  8. iani

    iani Guest

    Tape will work fine. Make sure you wrap the tape clockwise.
    kinetic and Coral reefer like this.
  9. Wlachnit

    Wlachnit Vice President

    I'm a Rectorseal user as well. I've also been told that the Teflon tape isn't meant for PVC pipe.

    Sent from my iPad using Tapatalk
    kinetic likes this.
  10. daddio

    daddio Supporting Member

    Are you sure it is not coming from the barrel? Put the rubber seal on the inside where it belongs?
  11. RandyC

    RandyC Supporting Member

  12. Yippee

    Yippee Supporting Member

    Formulated for drinking water. T Plus 2 (1).jpg T Plus 2 (2).jpg
    Wlachnit and ashburn2k like this.
  13. kinetic

    kinetic Webmaster

    Yes it's not coming from the tank itself. The rubber seal is on the inside already.

    Oh good! I'll probably skip Teflon tape and just goto Ace hardware to find RectorSeal.
  14. Coral reefer

    Coral reefer President

    That's what I meant by liquid teflon
    kinetic likes this.

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