Modern technology has drawn on the unique combination of properties of copper and copper alloys in
the form of tube and pipe products. Copper tube is used extensively to convey potable water in buildings and
homes. Copper alloys are selected to convey many diverse fluids for the oil, chemical, process and marine
industries. Copper tube’s second largest application is in air-conditioning and refrigeration systems; its fastestgrowing use in is fire sprinkler systems and fuel gas distribution systems in residential and office buildings.
Copper is used for plumbing tube principally because of its corrosion resistance, machinability and high level of
Measuring, Cutting and Joining Pipes
Copper is a soft metal and so can be easily cut and fabricated. It is also prone to damage, my develop
pinholes over time and can rupture from frozen water in pipes. Copper pipe comes in two flavors, rigid and
flexible. It has proven itself over the decades to be corrosion resistant and very reliable.
Rigid copper pipes are used for longer runs of water supply and in some cases also used as waste lines in
the home. Flexible copper is used in short runs for water supply.
Measuring and Cutting
Accurately measure the length of each tube segment. Inaccuracy can compromise joint quality. If the tube is
too short, it will not reach all the way into the cup of the fitting and a proper joint cannot be made. If the tube
segment is too long, system strain may be introduced which could affect service life. Cut the tube to the
measured lengths. Cutting can be accomplished in a number of different ways to produce a satisfactory
squared end. The tube can be cut with a disc-type tube cutter, a hacksaw, an abrasive wheel, or with a
stationary or portable bandsaw.
CUTTING COPPER PIPE
You can cut copper pipe with a regular hacksaw or a copper tube cutter. Although both will make a
satisfactory cut, the tube cutter ensures a square cut every time.
Use a jig or miter box when you're cutting copper pipe with a hacksaw. This helps to ensure a square
cut in the pipe.
You can make a jig from a wooden board or block with a vee notch sawed out to hold the pipe in place.
A slot in the jig will guide the saw at right angles to the vee notch, making it easy to hold the pipe while
cutting and helping ensure a square cut.
When using a pipe cutter, hold the copper tubing in place with a pipe vise or some other holding device.
After making the cut, remove the burrs inside the pipe with a half-round file. A pipe cutter usually leaves
more burrs in the pipe than a hacksaw.
When cutting pipe for a specific run, be sure to make allowances for the distance of pipe that fits into
the fittings. Also, remember to add the extra length the fittings will give the entire run of pipe. Figure
about 1/2" for each fitting.
The most common method of joining copper tubing systems is soldering with capillary fittings. Such joints are
commonly used in plumbing for water lines and sanitary drainage. Brazed joints with capillary fittings are used
where greater strength is required or where service temperatures are as high as 350°F (176°C). Brazing is the
required joining method for refrigeration and medical gas piping. Mechanical joints involving flared tube ends
are frequently used for underground tubing, for joints where the use of heat is impractical and for joints that
may have to be disconnected from time to time.
How to Sweat Copper Pipe
Sweating or soldering copper pipe is a basic plumbing process used in home repair or improvement
projects. Sweating a pipe and connector involves heating the cut end of a copper pipe and the connecting
piece, causing solder to melt and create a leak-proof union.
1. Cut your copper pipe to the desired length to fit your plumbing project using a pipe cutter,
which you can rent or purchase from a home improvement retailer.
Aim for a clean cut, free of rough edges by using a pipe cutter tool that has guides, which you'll
use to create a straight line.
Cutting can be done using a variety of tools, such as a hacksaw, an abrasive wheel or portable
or stationary band saw
2. Use sandpaper or an emery cloth to smooth the cut edges.
3. Test the fit of the copper piping and connectors before beginning by inserting the tube end into
the fitting cup, and then visually examining them to be sure they line up properly.
If you plan to work on a functioning copper pipe, be sure to turn off the water main or valve
4. Drain the water from the pipe by tipping the pipe if possible, or using cloth or paper towel to
absorb the liquid near the edge of the pipe.
5. Clean the pipe well, including the joint ends, using a wire brush.
After cleaning the pipe, wipe away any grit.
Cleaning the pipe removes oxidation buildup from the metal, which can cause a weak bond.
If you are connecting to a valve or other fixture, be sure it is open so you don't melt or warp any
6. Brush plumbing flux paste on the abraded connecting end.
Flux creates a clean surface for the solder, which will become the bond.
Only a small amount of flux need be applied.
Wipe away excess flux with a cloth.
7. Use a propane torch to warm the copper pipe fitting by holding the torch about 2 inches (5.1 cm)
away from the fitting and passing it evenly over the space for 10 to 20 seconds.
Be careful to avoid burning your hand on the pipe, which may become hot to the touch.
Melt the flux paste using the propane torch. A great deal of heat is not necessary; the paste will
melt at a relatively low temperature.
8. Assemble the connecting pieces by inserting the tube end into the fitting cup until you feel the
tube is resting against the base of the cup.
9. Heat the joined pieces with the propane torch.
Be sure to heat the joint evenly so the solder will melt evenly, creating a water-tight seal throughout
When the temperature of the pipe and connector reach slightly more than 140 degrees F (60
degrees C), the flux will begin to flow into the connector.
The copper will become glossy as the flux melts.
10. Remove the heat and apply lead-free plumbing solder to the connection when the copper begins
to appear dull and the flux crackles and begins to smoke.
If the joint is horizontal, begin at the base, move up to the top, and then down the other side.
If the joint is vertical, move the solder around the joint, covering it evenly.
If the copper is blackened or the solder beads, appears discolored or drips out, your pipe may
be too hot.
11. Apply more flux paste while the copper is still warm, and then wipe it clean with a cloth.
Do not try to cool the pipe rapidly with water or you may damage the joint.
Do not tighten the fixture you are soldering or move the joint until it has fully cooled.