1) Cut the pipe to length
Cut new lengths of copper pipe with a tubing cutter designed for copper. To use the cutter, twist the knob until the cutter wheel makes contact with the surface. Rotate the cutter around the tube, tightening after each revolution,
until the pipe snaps in two.
2) Ream the inside
After you've cut the tube, clean off inside burrs with a round file or with the retractable reamer often found on tubing cutters. Burrs can cause pipe friction, so reaming helps ensure a smooth-flowing joint.
3) Polish the pipe end
Use emery cloth, steel wool, or sandpaper to smooth and polish the last inch of the outside end of the pipe until it's shiny. Don't overdo it; soft copper sands easily.
4) Clean the fitting
Also clean the inside of the fitting from the end down to the shoulder. You can use the emery cloth or steel wool, but a pipe brush makes cleaning easier.
5) Apply flux
With a small, stiff brush, apply flux around the inside of the fitting and around the outside of the pipe end. Place the fitting on the end of the pipe, and turn the pipe or the fitting back and forth once or twice to spread the flux evenly. Then position the fitting correctly. It's best to wear gloves when applying flux, as the chemicals in it can damage your skin.
6) Light the soldering torch
Turn the gas torch's control valve on, and then light the nozzle end with a striker tool. Adjust the flame so it's steady and strong, making certain that it's not aimed at anything flammable. If necessary, shield surrounding objects with a flame guard.
7) Test the temperature
The joint is hot enough when solder will melt on contact with it. Test the temperature by touching the solder wire to the joint occasionally as you're heating the fitting. The instant the wire melts, the joint is ready for action.
8) Apply solder
Turn off the torch, and touch the solder wire to the edge of the fitting; capillary action will pull molten solder in between the fitting and the pipe. Keep applying it until a line of molten solder shows all the way around the fitting.
9) Heat the fitting
Next, position the torch nozzle about 4 inches from the fitting, and move the flame back and forth across the fitting to distribute the heat evenly. It's important to get the fitting hot but not too hot'the flux will burn and simply vanish if it's overheated.
10) Wipe off the excess
Once the solder cools (just a few seconds), wipe off surplus flux with a damp rag. Be careful'the pipe can get quite hot. Do not 
move the soldered joint for an hour or two, until the solder hardens.
Making a union
To install a union, first sweat-solder the male shoulder onto one pipe, and then slip the nut onto the other pipe. Sweat-solder the female shoulder onto the end of the second pipe. Bring the male and female shoulders together, and then slide the nut over the female shoulder, and screw the nut onto the male shoulder. To tighten, use two wrenches'one to hold the male shoulder and the other to turn the nut.
Complete Home Plumbing
All the plumbing know-how needed for repairs, remodels, or even building from scratch. Easy-to-follow text and pictures illustrate basic and advanced projects, from remodeling a kitchen to adding on a new bath or simply fixing a leaky faucet.
Copyright Sunset Publishing Corporation
