How to Repair Copper Tubing

Copper tubing is the most used, most-versatile, plumbing material around --- it comes many sizes and forms --- straight pipes and coiled rolls from one quarter to 12 inches in diameter. Most households have a mix of rigid pipe and flexible tubing to supply water to sinks, showers, baths and appliances. While it is usually hard to damage, it is not often hard to repair. The best method for repairing a damaged copper tube is to replace a the section containing the damaged pipe.

Copper tubing is joined in three ways: solder joints, compression fittings and flared tubing. In most applications you can mix and match the types of connections you make, for example, rigid pipes with soldered joints are often used to get water to the underside of a sink; compression or flared fittings are used on the flexible tubing that takes the water to the faucet.

Flared pipe connections require special tools. Solder joints require heating pipes with a torch and often fail when done by amateurs. Unless you need to replace a large section of previously soldered pipe with multiple joints, the easiest, safest and cheapest repairs are done with compression fittings.

Difficulty: Moderate

Instructions

Things You'll Need:

• Tape measure or ruler
• Tubing cutter -- there are special versions for working in tight spaces.
• Two adjustable wrenches or two fixed-size wrenches as needed for compression fitting
• Two compression union fittings
• Section of replacement tubing
• Steel wool

1. Figure out what size pipe you need so you know what you need when you get to the hardware store. There are three methods: First, look for printing on the existing pipe that tells you the size. Second, wrap your tape measure around the pipe you plan to repair; note the size. Or, if you already have a tubing cutter, remove a small piece of the pipe to bring with you to the hardware store. Also measure the approximate length of the pipe you'll be replacing.

2. Remove the length of pipe you'll be replacing, using the tubing cutter. Go slowly; you risk denting the tube if you apply pressure too quickly. You'll want a section long enough that you'll have some wiggle room when fitting the pipes, but give yourself clearance for the fittings near studs and other obstacles. Measure the length of the gap after the pipe is removed. Rub steel wool at the end of the existing pipe to remove any dirt or debris. It doesn't have to be shiny, but the compression fitting will need a smooth surface to hold properly.

3. Calculate the size of your patch pipe. The replacement pipe will not be the same length as the gap in the pipe; although the pipes slide into the union fittings, there is usually a stop point midway that takes up part of that distance.

4. Cut your patch pipe to length using the tubing cutter. Clean the inside ends of the pipe with the cleanup tool on the cutter. Use steel wool to clean up the outside of the pipe.

5. Slide one of the fitting nuts and a compression ring onto the replacement pipe, then slide on the fitting. Slide the compression ring to the fitting and secure by thumb with the fitting nut. Repeat on the other end of the patch.

6. Put fitting nuts and compression ring onto the existing pipes, then position the patch in place. This may require some gentle flexing of pipes to get them into the union fitting without damaging them. Slide compression rings against pipe and tighten by thumb with nuts.

7. Using two wrenches, one to hold the fitting and one to turn the nut, tighten the compression nuts. After all four nuts are tightened, carefully turn back on the water and check for leaks. Turn off water before retightening any joints.

Tips & Warnings

• Many modern homebuilders plumbed homes with few shutoff valves. It is a cost saver for them, but it make maintenance and repair plumbing more difficult. Depending on where you are working, a valve may serve as a better patch --- making your future pipe repairs easier. Copper tubes should be coupled to steel pipes using a special fitting, otherwise an electrochemical reaction can cause both pipes to decay.
• Natural gas appliances are often plumbed with copper tubing and flare-type compression fittings. It is highly recommended that professionals do all work on gas plumbing. Check your local codes; in many places professionals are required to do gas line work.

Resources

• More Information on Copper Tubing