Joining a copper pipe to a plastic one doesn't have to involve soldering, messy cement or even turning a wrench. Relatively new types of transition fittings, known as quick-connect or push-fit, require only some simple preparation of the pipes to be joined. Available from a growing number of manufacturers, these quick-connect fittings are increasingly the choice of both plumbing pros and novices for connecting any combination of copper, CPVC or PEX plastic pipe.
Clean the end of the copper pipe using steel wool. Make sure it's smooth and shiny for an inch or more, depending on the type of fitting.
Check the plastic pipe for any burrs or other irregularities that would interfere with the seal inside the new fitting. Clean CPVC very lightly with steel wool if necessary. Damaged PEX should be trimmed square with a utility knife.
Consult the manufacturer's instructions to determine how far the ends of the pipes must be inserted into the fitting. Mark this distance on the pipes with a felt-tip pen.
Insert the ends of the pipes into the quick-connect fitting one side at a time, making sure both penetrate the marked distance.
Turn on the water and check for leaks.
Check with your local building department regarding the use of push-fit or quick-connect fittings. Use only steel wool or a fine wire brush to clean pipe for this type of fitting; emery cloth is too coarse and can cause leaks. Quick-connect fittings can be removed using a special tool.