How To: Sweat Copper Pipes

Description

• Plan out your project carefully. If you can sweat several pieces together on the work bench before you connect them in place, it will make it much easier than doing it all in a confined space.
• Dry fit all the connections first.
• Turn off the water main or a valve between the point you are working on and the water supply. Water prevents a good solder joint.
• Stuff a piece of bread down the pipe between the water supply and where you are working. This keeps the work area dry. When you finish and turn the water back on, it will disintegrate the bread and flush it out.
• Drain the lines you are working with. If you have shut off the water main, turn on all the fixtures in the house, starting from the top floor. This will drain most of the water from the pipes and make your life easier.
• Always clean both surfaces you are going to join with sand paper or a wire brush. This removes the oxidation from the metal, which would otherwise affect the bond.
• Use lots of rosen/flux, this helps the solder get sucked into the joint you are making.
• If you are connecting a fixture, such as a valve, to a pipe, BE SURE to open the fixture. If you don't, the heat will build up and melt the internal seals of the fixture. Yes, I destroyed a valve this way.
• Make sure any lines that might be heat-sensitive are disconnected to the pipes you are working with. I melted a sink supply line by neglecting this one.
• If you cannot see all the way around the joint you are making, try taping a small mirror in place.
• Use the blue portion of the torch flame and apply it to the fixture, not the pipe. Don't heat the solder directly. Keep the flame near the point you are trying to apply the solder to, and work your way around the circumference of the pipe.
• It takes a while before the fixture is hot enough to start sucking solder. Be patient.
• If you don't get a good connection, don't try to fix it. Once all the rosen/flux is gone, it is really hard to get the solder to flow into the joint. Instead, remove the joint by cutting it away or de-soldering it, and start over. Really.
• After you are done, let the joint cool off by itself. Rapid cooling with water can damage the joint. Don't tighten the fixture you are soldering or move the joint until it has cooled.
• Before you turn the water back on, remove any filters like the airator on a sink faucet. When the water is turned back on, any junk (flux, sediment, bread) in the line will get flushed, and you don't want to gunk up your filters.

• Oxidation
• Water
• No solder flux
• Rapid cooling