Repairing Copper Sweat Joints

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by JL, Jan 1, 2007.

  1. JL

    JL New Member

    Jan 1, 2007
    Does anyone have a solid technique for repairing 1" copper pipe sweat joints that leak when first tested after being asembled? I am trying to decide whether to try and repair the faulty solder joints or cut the fittings out and start over.
  2. Gary Swart

    Gary Swart In the Trades

    Sep 1, 2004
    Yakima, WA
    It is my understanding that water precludes adding solder to a sweat joint. I'd cut the leaking fitting out and redo. It's likely you either didn't get the joint fluxed enough or didn't heat it enough. Regardless of the "why", I'd sure feel more secure with a new joint that I knew was done right.:)
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  4. Riosman

    Riosman New Member

    Sep 24, 2006
    San Diego
    Repairing copper joints

    I would cut it out if water was in the tube.
    I'm not a profession but have repaired and sweated on many times. Watched my Dad go thru the pain of learning as well.

    My mistake when learning.

    Over heating the tube during the sweat

  5. mowin

    mowin New Member

    Jan 1, 2007
    MAPP gas, super clean (even new), and don't forget the bread from ur sandwich to keep the water away from the new joint!
  6. Randyj

    Randyj Master Plumber

    Nov 25, 2006
    That's a good reason to test with air rather than water (when possible). I've had some luck just cleaning the outside heating and dabbing on some flux. A wet rag on a hot pipe cleans pretty good then dab on the flux and add a touch of solder... you get about a 50% chance that it will work. I've been able to heat it up and wrestle the fitting off re-clean then re-solder but for the cost of fittings I'd rather just put a new fitting on small pipe. I might give a little effort to more expensive fittings... replacing just a fitting is very time consuming that's why it's so very important to get really super clean, properly fluxed and soldered the first time. I know a few who say not to even touch a cleaned pipe because body oil or dirt on the fingers will contaminate the solder joint and I tend to work with it like it is "sterile" technique.
  7. Cass

    Cass Plumber

    Nov 12, 2005
    If you have a lot of leaks then your technique needs improving and I would redo all of them. Clean the fittings with a wire fitting brush, clean the pipe ends with sanding cloth, use Oatey #95 flux from Home Depo and any lead free solder.

    Heat the joints well. 2 thing that most beginners do is over heat the fitting and burn the flux black or not heat them enough.
  8. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    Once water has been in the pipe, it's either cut out the section and replace, or heat the fitting, pull it off, sand fitting and pipe, flux it, put back together and resolder.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Once water has passed through the leaking area, it is impossible to clean or flux it, so you either have to take it apart and redo it, (or cut the piece out), or be satisfied with "dabbing" solder onto the surface between the fitting and tubing and hope it lasts "forever".
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