Problem sweating second joint on a fitting

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by camner, Jul 22, 2009.

  1. camner

    camner New Member

    Messages:
    5
    It's been a while since I've sweated copper pipe, and I'm running into a new (for me, anyway) problem...

    I assembled the whole thing, cleaned and fluxed, and started sweating the joints. I noticed that the first joint on a fitting typically went very well, but the second one often didn't. The solder just wouldn't flow right.

    I think what was happening was that the flux in the second joint of the fitting was just getting oxidized out while I was sweating the first joint.

    How does one avoid that, especially on smaller joints such as couplers?

    And a second question...how likely is it that a joint that passes muster when first put under pressure will fail sometime later? Can I be fairly certain that a joint passing the initial pressure test will remain good?
  2. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    Practice...is the tubing open to the air some where so that your not trying to solder a closed system...?

    You are most likely getting the fitting to hot....try heating the whole fitting at the same time..
  3. Jay Mpls

    Jay Mpls Master plumber

    Messages:
    98
    Location:
    Minneapolis
    It is always my luck after the house has drained down I have to outlast or outwit water from something.Kind of sounds as though you *may* hae been fighting water.
    Every now and again I have expansion from the water heater to contend with.
    On a short closed system you may have been fighting pressure from your own heat.
    Beyond that, it's all in the preperation!
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,230
    Location:
    Cave Creek, Arizona
    solder

    Do not stop after each joint. Do one, usually the largest, then the next, and so on. For a vertical line do the lower joints first and then work upward.
  5. camner

    camner New Member

    Messages:
    5
    Thanks all for your help.

    It turns out the issue was flux. I originally bought a "kit" containing some solder, some flux, and a flux brush, and the flux was obviously not very good. I ran out, went to the store to get some more, and the guy there said "don't use that junk..try this!". And "this" worked wonders. Every joint I sweated after that worked perfectly (and I don't think my technique had miraculously improved, either!).
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