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Discussion Forum

TFE paste leak

ry91 | Posted in General Discussion on July 24, 2006 07:36am

Another plumbing question. I’m connecting the copper pipe for the showerhead to the rough-in with a threaded copper connector that is soldered to the pipe. I’ve tried three times to pressure test the joint with it leaking each time. The last time I cleaned all the threads VERY well with alcohol, and it dried for about 2 hours before I attmepted the third time. Am I missing something? Why won’t the paste hold? Is there a problem using it with a brass male and copper female connection? Thanks! Appreciate all the advise.

Ryan

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Replies

  1. User avater
    kanaka | Jul 24, 2006 12:25pm | #1

    Try wrapping some TFE tape over the paste. If that doesn't work, you may want to replace one of the fittings. Once had a copper male adapter with a hairline crack in it, and another time it was bad thread on the drop ear fitting.

  2. User avater
    SamT | Jul 24, 2006 06:05pm | #2

    Are you testing with water or air?

    What pressure?

    Water = 50-100 psi, air 5-15 psi.

    Water valves won't hold air pressure.

    SamT
    1. ry91 | Jul 24, 2006 07:01pm | #3

      Pressure tested with water.  I have a dual shower, and both sides leaked at the same place. Thanks, Ryan

      1. User avater
        SamT | Jul 24, 2006 08:48pm | #4

        Both sides of control valve? Exchange it.SamT

  3. woodway | Jul 24, 2006 08:55pm | #5

    Just to clarify, your attempting to attach a horizontal pipe nipple(short piece of pipe with threads at each end) between the shower head and the threaded fitting inside the wall. The piece inside the wall is a female pipe thread fitting, made of cast brass, which has ears on it to mount to framing.
    Use paste on both female and male threads and apply Teflon tape to the male thread before using paste. Use a 'strap' wrench to tighten the pipe nipple into the female fitting inside the wall, or channel lock pliers with some rubber inner tubing between the pliers and pipe to prevent scratches. A half turn past finger tight should be sufficient then check for leak, if it leaks tighten by 1/8 turn and recheck...repeat till no leaks.

    1. ry91 | Jul 24, 2006 10:24pm | #6

      Probably the same answer, but the situation is slightly different. This is to attach the nipple (which is soldered to the section of copper for the showerhead) to the rough-in. The nipple is soldered already to the copper, but the leak is between the nipple and the top of the rough-in. It's a Grohe 3-port rough-in, and is on the outflow port. Would it be better to solder the copper directly into the rough-in? I'd prefer not to.

      Thanks! Ryan

      1. woodway | Jul 24, 2006 11:27pm | #7

        If possible, try to get some photo's up and pointer locating location of leak.

        1. ry91 | Jul 25, 2006 03:56am | #8

          Here's a photo. Didn't have time to add an arrow to show where it is leaking, but it's at the top of the rough-in, where the output for the showerhead line goes.

          Thanks,

          Ryan

        2. ry91 | Jul 25, 2006 04:07am | #9

          Sorry, this one is rotated correctly. It's the top treaded joint.

          Thanks!!! Ryan

          1. BoJangles | Jul 25, 2006 04:50am | #10

            Those shower valve assemblies used to have female threads in them and people would overtighten the male pipe connections and crack the housing on the shower valve.  Now most of the bodies have male threads with the option of soldering the copper into the inside of the male fitting.  I would solder it and be done with the problem.  Just be careful not to apply any more heat than is necessary.  I have never had a problem soldering to those valves.

          2. plumbbill | Jul 25, 2006 05:25am | #11

            That joint looks awfully dry

            Put teflon tape on male threads then pipe dope over male threads then screw together.

            By chance you didn't solder that female adapter after you screwed it on to the Grohe did ya? 

          3. ry91 | Jul 25, 2006 08:45am | #12

            The joint is dry only because I took the picture just to show the joint I was referring to, not the way it was as I tried to connect it when the leak happened.

            I did try the tape plus paste and that held pressured water for 4 hours. Is that long enough of a test? Won't be under pressure while in use.

            I'd solder the joint if recommended, but nervous about soldering the rough-in. Would I take out the assembly or leave it in? Should I use a rag soaked in ice water to keep the housing cool? Other advise? Just don't think I'm fast enough yet to prevent overheating, but with good info I can do. Would you still recommend soldering? Would appreciate the info even if you think soldering is unnecessary, for future reference.

            Thanks! Everyone is a wealth of info, and I appreciate it!

            Ryan

          4. plumbbill | Jul 25, 2006 02:41pm | #13

            We have both soldered & screwed valves on our jobs it was more of a preference on who was running the fab shop I think.

            We installed about 250 Grohe Atrio¯ PBSV's on our current job, most were gutted.

            But that was how they were orderd from the factory.

            4hr pressure test is more than enough time.

            UPC rallows 3 different tests. working system live test---- hydrostatic 1.5 times the working pressure----- or an air test of 50 psi any of these test are only required for a period of 15min. 

          5. ry91 | Jul 25, 2006 08:20pm | #14

            Sounds like it's gonna hold.

            So when we do our other bathroom, and I decided to solder the joint instead, would you recommend gutting it to solder? Any other steps to keep the housing cool?

            Oh, and what does PBSV stand for?

            Appreciate it! Ryan

          6. USAnigel | Jul 26, 2006 12:16am | #15

            I would suggest you remove any rubber/plastic parts before heating for solder.

          7. BoJangles | Jul 26, 2006 12:19am | #16

            You don't have to take it apart to solder it.  You can make all of the copper to valve connections at once before you mount it.  It is a lot easier to position it for soldering if you do it that way.  A wet rag on the part you aren't heating helps out.  I think you are more likely to cause yourself a problem by taking it apart than you are by carefully soldering it with a propane torch.  There may be a few easily removed trim parts you could slip off before soldering.

            Edited 7/25/2006 5:23 pm ET by BoJangles

            Edited 7/25/2006 5:33 pm ET by BoJangles

          8. plumbbill | Jul 26, 2006 06:33am | #17

            PBSV = pressure balance shower valve.

            To take apart or not to take apart----- that is the question.

            The answer will vary more than repubs & demos disagree on stuff.

            In my expierence I think it comes down to preference.

            I don't take them apart nor do I use anything to keep the valve body cool either, BUT I do this for a living & have been doing it for about 25 yrs.

            I have seen plumbers with more time in than I, & they won't touch one without taking out the guts.

            If you take it apart there is NO chance of burning up the rubber & plastic parts.

            If you want to leave it together to save time---- I will suggest putting a wet rag on the body.

            Point tip of torch away from valve body.

            Heat pipe & valve equally 2 seconds on pipe 2 seconds on valve etc.........

            Don't dilly dally----- heat -- solder-- wipe-- be done.

            Todays water soluable flux's don't require as mush heat as the good old acid based flux's of yesturday. I should add that water soluable flux's burn out of the joint faster than acid based. 

          9. rich1 | Jul 26, 2006 07:25am | #18

            I think it also depends on how many you do. Screw up 1 out of 100, cheaper to repair 1 than to remove and replace guts from 100.

            Only do 1 a year, take out the guts, cheap insurance.

          10. plumbbill | Jul 26, 2006 08:25am | #19

            Yup

            Like I said if ya remove the guts you can't burn it up. 

          11. ry91 | Jul 26, 2006 08:34am | #20

            I've been using a propane torch. I use the inner blue flame to heat the fitting. Everyone has told me, or I've read to heat the fitting, not the pipe. Is it different when soldering to valve bodies? (you mention heating 2 seconds each pipe and valve body) Also, I keep hearing/reading it only takes a few seconds to heat enough to melt the solder, but it has taken me at least 10 seconds, usually more. I'm using a petroleum based flux with a 95%/5% silver solder. Could I be doing something wrong?

          12. User avater
            kanaka | Jul 26, 2006 12:52pm | #21

            Try MAPP gas. Burns hotter and really cuts down on the cooking time. Just make sure you torch head can handle the extra heat. I use a Turbotorch. Also, a plumber friend told me it takes more heat to melt 95-5 than it does silver bearing solder, which is 2% silver. I understand it holds better,too. But it's also more expensive.

          13. plumbbill | Jul 27, 2006 04:26am | #22

            When I said 2 seconds on each----- that was to keep the torch moving so you don't develop a hot spot & burn out the flux. Standard 1/2" with MAPP gas can take up to 20 seconds to get solder to melt, but if you put torch in one spot for 20 seconds you run the risk of burning out the flux.

            If the fitting turns black & the solder beads up & falls off then it is too hot.

            Generally we heat the fitting twice as much as we heat the pipe.

            I said to heat more on pipe when guts are still in valve--- I should have been more specific. 

          14. ry91 | Jul 27, 2006 08:19am | #23

            thanks everyone for all your advise.

            Ryan

          15. carbon | Jul 28, 2006 04:11pm | #24

            I've only done this once, but it took me an amazingly long time to

            heat the valve on my Delta 1704 valve with a propane torch.

            I heated the valve at least 4 times as much as the pipe. I'm sure

            glad I took the guts out! I'd never had to turn the propane up so high,

            either.

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