Tutorial on Sweating Copper Joints

Yesterday I showed you how to cut copper tubing using a tubing cutter.  Once you have your tubing cut to length, you're going to need to somehow connect it to the fittings how you want.  The traditional way to do this is by sweating the joint, which is the plumbing term for soldering.

The tools you'll need are:
  • A propane torch.  If you're only doing small joints for crafts you might be able to get away with smaller crafting torches, but if you're trying to joint long lengths of tubing, appreciate that all that copper acts like a heat sink while you're trying to sweat the joint.
  • A flint sparker or other torch-lighting mechanism, if your torch doesn't happen to have a self-ignition system.
  • Steel wool.  This is used for cleaning up the surface of aged copper tubing and removing oxide to ensure a good joint.
  • Plumber's flux and brush.  This is important, because without flux the solder will just roll off the copper and not suck into it like it needs to.
The one thing to note in the video is that I interchangeably call the joining alloy solder or lead.  Technically it is 40% lead and 60% tin, so I misspoke in the video.

This is all explained in the video, but the steps to sweating a joint are:
  • Clean all surfaces to be joined with steel wool until shiny.
  • Apply flux to ensure good connection between the copper and solder.
  • Join the fittings and apply heat to the whole connection.
  • Touch solder to a single point on the joint, and enjoy seeing it magically suck in to make a solid joint.
    • Be careful while applying solder that you don't apply too little solder, but once you apply enough, the excess will drip from the bottom of the joint.  Try not to burn yourself.
 This is the finished joint.  Notice how the solder readily sticks to the surface of the copper.  If your solder just beads up and runs off, you need to clean the surface again and apply more flux.
Since I'm using this for crafting and not actual serious plumbing, I also take the time to hit the joint with a wire wheel to clean off the excess burnt flux once I finish.  It cleans off very easily.

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