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Discussion Forum

Sweating a threaded copper fitting

Jemcon | Posted in General Discussion on March 26, 2007 12:23pm

Does anybody have a solution for sweating a threaded fitting onto a pipe after the pipe dope is on and the fitting is threaded in?

What I mean is if you have a MPTxC fitting for a copper water line and you need to thread the fitting into a valve before you sweat it onto the existing pipe how do you keep the pipe dope from cooking and then leaking?

My only thought is to use unions on both sides but I don’t know if union are allowed before the water meter in a house.  Thanks, Jeremy

 

 

 

Headstrong, I’ll take on anyone!

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Replies

  1. User avater
    NickNukeEm | Mar 26, 2007 12:32am | #1

    Unions would work.  If there is enough straight line prior to/after the valve, sweat the fitting to a length of tube, install in valve, and use a coupling to join the valve assembly.  Depending on the length prior to the valve, wrap the fitting with a damp rag to protect the dope while sweating. 

    I've never sweated a fitting with dope on it, so I can't say what would be the reaction.  I've always been able to pre-assemble.

    Maybe a real plumber will be by to give you the real 'dope'.

     

    "I am the master of my fate, I am the captain of my soul."  Invictus, by Henley.

  2. BoJangles | Mar 26, 2007 12:32am | #2

    Is this on Type K copper coming in to your house underground??

    1. Jemcon | Mar 26, 2007 12:56am | #3

      I belive it is type k. I comes up through the slab and then 90's to the meter. It's the dw's cousins house. He want's a Water Cop in the line before the meter. He had a water line break going to the humidifier in the attic and it made a big mess. 

       

       

      Headstrong, I'll take on anyone!

      1. BoJangles | Mar 26, 2007 02:25am | #4

        Is there a fitting where it 90s to the meter?  Maybe you could sweat it off and start working backwards.

        I frequently sweat fittings that are already doped and don't seem to have a problem if you've got good pipe dope, but it would be a lot better to avoid it if possible.

        A wet rag over the threaded fitting helps if all else fails.

  3. User avater
    DDay | Mar 26, 2007 02:49am | #5

    Pope dope is designed to take the heat from what you are doing. Every day plumbers and Heating installers do the same thing and it never is a problem.

    Bojangles mentioned what I'll do if Im near something I don't want the heat to get to, like a valve or pex, etc. Use a wet rag or cloth and this keep the heat down quite a bit.

    1. WillieWonka | Mar 26, 2007 06:57am | #11

      You said Pipe dope is able to take the heat of a torch?? Would that include Acetylene? And is that true for most dopes like Hercules, Gasoila, etc? How close can you solder to a doped fitting? I never tried it before, for fear I'd cook the dope, dry it out, or make it lose it's sealing properties. It'd be nice to know I"m fully safe if I ever had to solder right next to a doped fitting, though.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time.  -ME

      1. BoJangles | Mar 26, 2007 03:26pm | #13

        I use Gasoila dope only and have soldered next to it hundreds of times and never had a leak.

        1. WillieWonka | Mar 26, 2007 03:43pm | #14

          Wow, ok, thanks. I never knew. The can directions never say anything about sweating near it, so I always followed the when in doubt rule.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time.  -ME

      2. User avater
        DDay | Mar 26, 2007 07:09pm | #16

        As bojangles said, its not a problem at all. I have a few friends that put in 3 or 4 heating boilers a week and they solder next to dope all day and never a leak. You don't want to run a torch over the dope for a long period of time but soldering near it is fine.

  4. inperfectionist | Mar 26, 2007 02:54am | #6

    Teflon tape.

    You want to install this valve before the meter?? City might not go for this arraignment. Think about putting the valve downstream of the meter. How are you going to shut off the water to do this work??

    I do lot of my own plumbing, but what your doing, I'de call a plumber.

    Harry

    1. Jemcon | Mar 26, 2007 03:23am | #7

      There is a shut off before the meter where the pipe comes through the floor. After the meter it tees off and they want to protect the whole house.

      I'll shut off the valve and install the Water Cop from there. There's only about 9-12" from the valve to the elbow so I'll see how it will fit. 

       

       

      Headstrong, I'll take on anyone!

  5. JTC1 | Mar 26, 2007 04:46am | #8

    Already been mentioned a couple of times, but I'll "third" it or so - strip of wet rag wrapped around the threaded section should be enough to protect the pipe dope. 

    Jim

    Never underestimate the value of a sharp pencil or good light.

     

  6. ponytl | Mar 26, 2007 04:55am | #9

    if it's an issue just use a compression fitting or a shark bite...   i pride myself on being able to sweat joints that look pretty and don't leak...  but  i have grown to really like compression fittings...  used my first shark bite a few months ago on a leaking line without cutting the water off...  long story on why i couldn't  but  with a bunch of rags me in a garbage bag and some buckets... i cut and capped a 3/4" water line with a cut off attached to a sharkbite in less than 5 seconds.... from full cut to capped... very little clean up... capped it with the valve open  once it snapped on i closed the valve...  ( had the open side of the valve rigged to a garden hose run'n into a bucket)

    i believe ... in sharkbites

    p

    1. Jemcon | Mar 26, 2007 05:01am | #10

      I can't find 1" compression fittings. I carry for 1/2 and 3/4" lines but never found for 1". According to the Hercules website, they recomened the wet rag deal. So i'll probably try that. 

       

       

      Headstrong, I'll take on anyone!

      1. User avater
        BillHartmann | Mar 26, 2007 07:20am | #12

        What I have done is to solder a 4-6" stud to the fitting.Screw it in place. Then wrap a wet rag around the fitting and stub.Then solder the other end of the stub into a coupling or 90 or whatever..
        .
        A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

        1. Shacko | Mar 26, 2007 06:45pm | #15

          Good post Bill, if you keep this up you may lose your tag-line!, lots of luck.........................................
          "If all else fails, read the directions"

    2. rez | Feb 28, 2009 11:04pm | #17

      Just read that story in a different thread. Actually was pretty cool. Been worthy of a teaching video me thinks.

      Where's Huck? 

      94969.19  In the beginning there was Breaktime...

      94969.1  Photo Gallery Table of Contents

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