Sanded the pipe and fluxed the elbow

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Thatguy, Sep 27, 2010.

  1. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    , did not flux the pipe, and the replacement 3/4" elbow leaks like a sieve.

    I was putting a light in a closet and somehow drilled through a water line support block and then into the water line right at the elbow. I should have put tape on the drill bit to use as a depth gauge.

    Now I'm waiting for the water to drain out so I can apply more solder.

    With a mirror it appears that I don't have solder all the way around the backside of the joint but I can't say for sure that that's where the water is coming out.

    This almost never happens to me.

    What could I have done wrong with the prep and the soldering? How do I recover from this? Does the joint have to be cool enough to touch before I can pressurize it?

    Fortunately we still have water in the other half of the house thanks to ball valves I had a plumber install.

    Thanks for whatever you can tell me.
    Last edited: Sep 27, 2010
  2. Redwood

    Redwood Master Plumber

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    Pull it apart, clean everything, flux it, then sweat it up again...

    I can't tell from here what you did wrong....
  3. ballvalve

    ballvalve General Engineering Contractor

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    northfork, california
    Stuff some wonder bread into the pipe and flux it with a tinning flux.
  4. Gary Swart

    Gary Swart In the Trades

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    It sure sounds to me like there was some moisture in the pipe. It doesn't have to be stand water, and it doesn't even have to be close to the joint. Water, when heated, turns to steam and that will prevent solder from flowing. It may be overkill, but I apply flux to both the fitting and the pipe. Do what you have to do to get the inside of the pipe 100% dry.
  5. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    I always cheeck and double check my joints are dry before I solder them. Sometimes that means draining down to a very low fixture.
  6. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    Got two more 90 elbows at HD and peeked in their plumbing book. Apparently I've been lucky so far. You shouldn't touch the bare copper joint surface with your fingers, you have to wait 15 minutes before using the joint and this time I fluxed both surfaces.

    Hacksawed the 2nd elbow off and mounted the third. Use pliers to roughen up and remove old solder, then sanded the surfaces.

    I'm still in the 15 minutes.

    How much of 1/8" thk solder should go into one of these joints? I probably used 1".

    Thanks, guys. . .
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    The other thing that can get you is if the pipe isn't open somewhere near. The heat from soldering can expand the air enough so that it can shooot a small hole through the molton solder. It's much worse if there's any moisture, as steam expands much more than just the air itself.
  8. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    Thanks all.
    Tomorrow I call a plumber.
    Each one of the three leaked less and I guess it was always on the same side.
    I'm now thinking it was steam, and I should have used the bleeder screw on the nearby ball valve to let it out.
    If the plumber can't make it in a day or two I may try again.

    I did see a 3/4" compression elbow on the Web but finding it locally may be a problem, and I don't know if flex elbow couplings can withstand 50 PSI.
    Last edited: Sep 27, 2010
  9. Terry

    Terry Administrator Staff Member

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    Bothell, Washington
    Whenever you are soldering, you have to have an open end to allow steam to escape, otherwise the pressurized air will blow the solder out of the joint.
    Don't feel too bad, I had a journeyman plumber argue this point with me on a retirement home. I told him not to do it, but wanted to so bad, that he soldered a 2" pipe and fitting without propping open the check valve. Needless to say, we had a real nice leak on the 2" fitting that he insisted wouldn't leak. I wanted to smack him on the spot for having to explain to all the doctors, nurses and people living in the retirement home, that had already been waiting for the water to come back on after cutting in the new water heating system.
    Always have an open end while soldering, sometimes this can be done by opening a faucet somewhere.
  10. SteveW

    SteveW DIY Senior Member

    Messages:
    1,052
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    Omaha, NE
    Yep, I've been snookered by steam myself - it can sneak up on you and ruin a joint that you've properly cleaned, fluxed, and soldered. I learned that on this site! I thought I had "lost my touch" with sweat soldering until Terry educated me on needing to leave an exit route for the steam.

    As another option, you could go with a Sharkbite elbow...
  11. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Yes, flux should go on both pieces, and touching bare copper can foul the joint. 1" of solder is plenty for a 1/2" or 3/4" fitting. If you can "remove" solder from a fitting or pipe with pliers, it was not bonded.
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,510
    Location:
    Cave Creek, Arizona
    I do not measure the solder when I make a joint. You can pressurize a solder joint almost instantaneously, (usually the time it would take you to get to the shut off valve is more than enough time), you do not have to wait 15 minutes. Your tubing and fitting may not be NOT cleaned properly, especially if the leak is always in the same place. You don't use pliers to remove the old solder, you use a torch and a rag.
  13. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    He turned off the main water supply and did some draining of all the pipes.
    New elbow, a splice and two new short pipe sections to realign the joint. He worked ~30 mn & charged $110.
    For my leak he said it coulda' been steam, bad alignment and/or dirt.

    I have to say that acetylene sure burns hotter than propane. And louder.

    He said he didn't like Sharkbites because the pipe axis alignment had to be precise.

    Now I can get back to putting in that closet light.

    Thanks, folks. . .the next job is putting in a new sillcock but I don't expect anywhere near this kind of trouble.
    Last edited: Sep 28, 2010
  14. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Glasd you got your job fixed, and at a reasonable price.

    Soldering is certainly something that can be accomplished by a homeowner. I suggest you do some practice. Take some pipe and fittings out to your workbench, or even out to the sidewalk.
    Just solder up a lot of joints. You will develop the "feel". You will see that faint greenish glow when the heat is just right. You will learn how to heat the joint QUICKLY....so the flux doesn't burn out. Holler up if you have more questions.
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