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Copper sweat joining 2 pieces getting stuck

tombarton23 Member Posts: 1

Saw an old listing at this site by John in 2006 and I am, like John, an amateur plumber. But couldn’t resist to mention here I had the same issue today in 2024, that John did in 2006. Story. Soldering 1/1/ 2 copper elbow to a straight piece and prior to sweating the slip those to pieces joined nicely, and tight. Then put on the flux. Oops! A problem. Slip on suddenly not so easy. In fact it got stuck part way in and I had a heck of a time getting it out. So after much ado , frustration and banging……. the darn thing finally came off. Started over. Did some more good, solid sanding, of the copper. Wiped it clean. Tried again. Still no improvement, no slip. Tried this, tried that. Then went to the kitchen sink and after cleaning both copper pieces with soap and water, the easy, normal, slip, was back. Slipped right in. But why? I thought it was the kitchen hot water, heating the pipe. I thought it was the residue soap in the water. So I rushed to re-flux both pieces and STILL, no slip, same story. The union was not happening and getting stuck part way in, yes, again. So I took another half an hour of time separating the elbow from the straight piece of copper. And back to the sink. Cleaned them, then tried a different flux. Flux? Remember flux. And surprise, surprise surprise. BINGO! The newly purchased , regular brand flux was the issue. Still shocked that flux was the issue that was causing all the getting stuck. After all it’s a liquid and still should cause some slide, not a getting stuck event, not a non fitting experience. Weird. Anyway I changer flux and even used my old dirty flux as the replacement which I grabbed out of the trash can. And the slip was back. The sweating resumed. Finished, no leaks. Sometimes the answer is right in front of us. Plumbing may look easy but it’s fixing the problems that can come up along the way that makes a plumber a good plumber. I was sure glad to resume my regular job the next day, delivering the US Mail and I’m going to leave plumbing behind me after that experience. Hopefully sharing it though will help some other amateur plumber, before he or she gets stuck.


Mad Dog_2SuperTech


  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,205

    Alot of guys say plumbing is easy until they actually try it. If you file off the rim of the copper tubing & get all surfaces of tubing & Fitting shiny, the only problem you can have is poor quality foreign tube or fittings, meaning a poor fit. Mad Dog

    EBEBRATT-Ed Member Posts: 15,764

    Or the pipe and or fitting could be slightly out of round. Or when connecting the pipes together the pipes are out of square, so the fittings bind. That is usually the issue. What @Mad Dog_2 mentioned could be caused by a dull cutter wheel in your cutter.

    Doing copper is pretty easy until you get jammed in a tight spot. Just takes some practice and experience which come with time.

    Just like delivering mail. I am sure your better at it now than when you started.