Sweating copper pipe problem

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by musicis, Jan 2, 2008.

  1. musicis

    musicis New Member

    Jan 2, 2008
    Finish basement at utility sink. After cutting off the copper hot/cold supply, I still get just enough water to wet the sanded copper I am trying to sweat. I opened up all the valves on the first and second floor. Even after a half hour, I still got some water. It will not drip out until I try to dry it with paper towels. I put shut off valves in the wall in the meantime. But tomorrow I need to remove the valves and do some sweating to accommodate the utility sink and the washer/dryer. I assume it has to be dry completly before the sweating? There is just enough water that it will get on the flux. Any ideas would be greatly appreciated.
  2. Mike Swearingen

    Mike Swearingen New Member

    Jan 12, 2005
    Independent Real Estate Broker
    On Albemarle Sound In Northeastern NC
    You can't solder anything with water in it or dribbling through it, as you know. You can get temporary "plugs" made for the purpose that will melt out after you finish soldering, or you can just use the age-old standby temporary "plug" of a white bread ball (no crust). When you turn the water back on, make sure that you don't open a faucet with an aerator on it first (use a tub faucet or outside spigot or remove an aerator) to allow the dissolved bread to flush out.
    Good luck!

    Last edited by a moderator: Sep 5, 2009
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  4. parry

    parry New Member

    Nov 30, 2007
    Use acetylene. Heat the joint evenly. Biggest mistake people do is heating the solder and trying to force it into the joint. Heat the joint and the solder will slide right on in.
  5. frenchie

    frenchie Jack of all trades

    Dec 30, 2006
    Brooklyn, NY and Fire Island, NY
    If you have an open drain point somewhere between the leaking shutoff and the place where you need to sweat, a shopvac can help - suck all the water out there, so it doesn't get here. Then heat the pipe, before cleaning, to evaporate any residual dampness. Let it cool (shopvac running the whole time), clean, flux, fit, sweat. A bit noisy, but it works.
  6. Cass

    Cass Plumber

    Nov 12, 2005
    I think you mean propane or MAP gas.
  7. Wet_Boots

    Wet_Boots Sprinkler Guy

    Mar 23, 2007
    Metro NYC
    If there isn't already a drain on the house supply, one might consider undoing one of the union fittings on the basement water meter, to let the excess water dribble out. There are also ball valves made with compression ends, that can be cut into a copper line, without having to solder anything.

    Jet-Swet tools will close off the dripping water, if you have enough straight pipe for the tool to work in. There is another manufacturer's version that is supposed to work around curves, but I've never tried them.

    (why not acetylene, if you have the B tank and torch? - cheaper than MAPP, in the long run)
  8. davefoc

    davefoc New Member

    Nov 7, 2006
    It might be the Pasco Quick Sweat that you're thinking of.


    I'm not a plumber and don't do enough copper pipe soldering to justify an $85 tool for this purpose but it looks ingenius to me.

    The Jet-Sweat tools always looked too limited for anything I imagined myself doing and they were way more money than I could justify for my purposes.

    The only time I've had this problem was when I needed to cap a pipe that was lower than the lowest opening in the pipe system and the building had a faulty (of course) gate valve for the shut off. I opened everything up as well as I could and stuffed a small piece of rag down the pipe. It worked fine, at least until the rag drops out and blocks an outlet someplace else.

    ETA: I wondered if the opening poster wasn't too worried about "dry completely". If the pipe and fitting gets hot enough to boil all the water away and melt the solder readily that's good enough I think. It's only when the water keeps coming too fast for the pipe and fitting to heat appropriately that there is a problem (in my inexperienced humble opinion of course).
    Last edited: Jan 3, 2008
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    Steam will make little channels through the soldered fitting, or, force the fitting off. Those voids really make for problems. You really need to get it dried out first.
  10. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    When draining down a home, the quickest way is to open every faucet, tub, and shower valve in the house. Otherwise, the water will keep weeping down the pipes forever.

    When soldering, make sure there is an open outlet somewhere.
    You can't solder a closed system.

    Now you know why Sharkbites are so attractive for service work.
    You can just slip those on.
    I still prefer soldering though.
  11. musicis

    musicis New Member

    Jan 2, 2008
    I shut down the main today at 9:00 am. I opened every valve in the house. It took an hour for the water to finally stop. It is a huge mansion type house. All was well after that. Thanks to all for the replies. Home depot wanted 7 bucks for those plugs. I did other work while the drain dried up. I did buy them but will be returning them on the weekend. :)

    It could be that I did not open the outside valves that was the problem. But it was 2 degrees out there. :(

    Nice to get a post from the man himself!!! :)
    Last edited: Jan 3, 2008
  12. KirbFeeler

    KirbFeeler New Member

    Nov 18, 2007
    Keeping My Wife Happy ;)
    Central Illinois
    I had this problem a while back due to a leaking main gate valve. My solution was to wrap some bare solid copper wire around a wad of cotton cloth to make a plug,. Slide the plug into the pipe leaving the wire handle sticking out, then slide a valve (or half of a union as I did) over the wire onto the pipe and sweet into place. Worked Great!
  13. coz

    coz New Member

    Feb 27, 2007
    sometimes compression fittings are handy also.
  14. SteveW

    SteveW DIY Senior Member

    Feb 11, 2005
    Omaha, NE
    I know this has been said here in another thread but in case anyone doesn't know -

    You can buy Sharkbite fittings with an integral 1/4 turn ball valve in 1/2" and 3/4" sizes. W

    I am tempted to buy one of each just to keep in the house in case of emergency. Would come in really handy if you have to get a shutoff on a 'hot' pipe.
  15. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Use acetylene.

    As if every homeowner has an acetylene torch available, and by the time they pay for a Jet-Swet, they could pay a plumber to do it and be done in a matter of minutes.
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