The Basics of Working with Copper Pipe
If you live in a home that was built in the past 50 or 60 years, your water supply is quite likely built of copper tubing. In earlier days, iron pipe was the standard for residential construction, but iron is heavy, awkward to work with, and requires a lot of specialized tools like pipe threaders. Plus, the fact that iron deteriorated over time meant it wasn't always the best option. Copper, on the other hand, is light, relatively easy to work with and doesn't waste away so it has become the standard for water supply pipes in the modern world.
Types of Copper Tubing
There are two types of copper tubing, known by their highly technical names as "hard" and "soft." Actually, the proper names are "tempered" for hard pipe and "annealed" for soft, but those names are very rarely used. Hard pipe is used in new construction and renovation where it is relatively easy to gain access to the inside of the walls or exposed pipes. Soft (or flexible) pipe is more often used in repair work, since it is easily bent around existing obstructions.
Both hard and soft copper pipe come in a range of standard sizes, from 1/4-inch all the way up to two-inch. Average homeowners will most likely run into pipes that are 1/2-inch (used for tub and shower supply lines), 3/8-inch (kitchen and bathroom taps), and 1/4-inch (toilet supply lines and refrigerator ice makers). The larger sizes are used primarily for supplying water to a building or in outdoor construction.
Copper pipe also comes in various thicknesses, designed for different applications. Type M is the most common type of copper pipe sold. It's relatively thin walled, but it does meet most building codes and is used in lots of residential construction, primarily for running water pipes to fixtures. Type M copper pipe is marked with red lettering.
Type L pipe is thicker walled and used for providing water services or in places where the pipe will be exposed. Some contractors will use Type L for home construction, and building codes in some jurisdictions do require Type L for residential buildings. This kind of pipe is identifiable by its blue lettering.
Finally, Type K is the thickest and is primarily used for running pipe from water mains to a meter or in underground lines. Type K pipe is marked with orange lettering.
Tools for Working with Copper Pipe
Working with copper pipe is fairly straightforward. It requires some standard tools that most homeowners already have—a measuring tape, drill and spade bits, marker, hammer, and adjustable wrench—as well as a few specialized but inexpensive tools that will make the job easier. A pipe cutter (at right) is a worthwhile investment when working with either hard or soft pipe, since it will give you a straight and fairly clean cut (although you can still cut copper pipe with a hack saw).
Other tools needed for hard pipe are a propane torch, emery cloth or steel wool, lead-free solder and flux, and for safety, a spray bottle filled with water, gloves, and eye protection. If you're working with soft pipe, in addition to a pipe cutter the only specialized tool you would need is a flaring tool. This is a tool that widens out or flares the end of a pipe, preventing a fastener from sliding off the end once you've put it on.
Small pipe cutters are available that allow you to work in confined spaces. Because they're smaller, they don't require as much free space around the pipe for you to rotate them, but they also don't provide as much force as larger ones.
Installing Copper Pipe
Hard copper pipe is relatively easy to work with when you can get to the studs behind a wall. Use a spade bit to drill a hole slightly larger than the pipe itself and thread the pipe through the hole and between the studs. It's rigid enough that on straight runs, you don't even need to reinforce or support the pipe.
However, just as the name implies, hard copper pipe is stiff and doesn't bend. To run pipes around corners or even make bends and joints in the pipe, you’ll need to cut it, attach special fittings, and continue the run after the fitting. Some common fittings are T-couplers (which allow you attach a branch line off a straight run), 90-degree elbows (which bends the pipe run around a corner), and 450 degree elbows (which bends the pipe run at a 45-degree angle). Hard pipe comes in 10 and 20-foot lengths that you will cut to length or joined with fittings.
Attaching fittings or joining hard copper requires soldering the pieces together (sweat soldering). Soldering joins two pieces of copper with a metal—the solder—that actually bonds with the copper. After the joint cools, the end result is a joint that is as strong as the original copper itself.
Soft copper tubing comes in rolls ranging from 20 up to 100 feet, although you may be able to buy smaller lengths at a home store. It bends easily and works well in applications where space is tight. Since you can bend it, a run of soft copper pipe doesn't need as many joints as a run of hard pipe. However, since you can't solder soft copper pipe, you need to leave any joints accessible and can't hide them behind a finished wall.