Pipework–Joining, Cutting and Bending Pipes

At one time all plumbing work was done with lead pipe (the word “plumbing- is derived from the Latin for lead). Then iron pipework (galvanised to stop it from rusting) was introduced. Many houses still have pipes in these materials, which are not practicable for the do-it-yourself plumber. On the other hand, copper pipe can be handled by the amateur.

If you want to extend the pipework in your home — to plumb-in a washing machine, for instance, or install a washbasin — there are three basic processes to carry out. First the copper pipe has to be cut to length. Then it has to be joined. Finally, it has to be bent for corners.

Sizes of pipe.

The three principal sizes of pipe are 1 in. 3//4 in. and ½ in. The accepted metric equivalents in pipe sizes are 28 mm, 22 mm and 15 mm respectively. The 1 in. diameter pipes are used mainly for carrying water to and from the boiler and the hot cylinder. Pipes of in. diameter are for general plumbing work, such as taking water to sinks and basins, while in. pipes are for small branch lines.

Joining up pipework.

To connect lengths of pipework, you use joints: straight ones for joining straight lengths of pipework; T joints to make a branch line; elbow couplings to take pipework round a corner. They work in two main ways.

The compression joint is the easier to use. It consists of a threaded body with a nut and a small copper ring known as an olive.

1. Slip first the nut, then the olive on to the end of the pipe.

2. Bring the body of the joint to the end of the pipe and slide the nut and, with it, the olive back to meet the thread.

3. Tighten the nut. This action will crush the olive, thus forming a waterproof joint. Do not over-tighten the nut or leaks will result. Tighten it as fully as you can by hand. Then use a spanner according to the manufacturer’s instructions. One full turn with a spanner usually suffices.

The capillary joint, the second type of joint, incorporates rings of solder inside its body. You coat the end of the pipe with flux, push it into the joint, then play a blow lamp flame on it. Immediately a thin bright silver ring appears around the entrance to the joint, you will know that solder has flooded it and you should withdraw the heat. Too much heat, and the solder will run out too far; not enough, and it will not flood the joint completely. In either case, you will get a weak or leaky joint.

Cutting copper pipe.

Since copper is a soft metal, copper pipe can be cut to length with a hacksaw. But if you intend doing a fair amount of plumbing work, invest in a pipe cutter. This will cut accurately without flattening ends, which makes it difficult to ensure watertight joints. Always thoroughly clean and tidy up the end afterwards with emery cloth or a fine file.

Bending pipes.

Where you have to bend a pipe to take it round a corner, you may be able to do so on your knee, provided the pipe is of no greater diameter than ½ in. or ¾ in. Tie a pad of old rags around your knee. Position the pipe so that the centre of the proposed bend is on the point of your knee. Hold each end of the pipe and jerk. To stop the pipe from flattening, insert a length of spring (known as a bending spring) in the pipe with its centre at the centre of the proposed bend.

Fitting waste pipes. Plastic piping serves for waste pipes. It is easy for the amateur to work. You can cut it with a hacksaw or even a fine tooth tenon saw and join it with couplings like those used in copper piping. Some couplings require a jointing cement to fasten them in place: others have sealing rings that involve merely a push fit. The waste pipe needs a U-trap.

So that the waste pipe can pass through to the outside drain, you must pierce a hole through the wall of your house with a cold chisel and heavy hammer. If the house has a cavity wall, ensure that as little debris as possible falls into the cavity. When the waste pipe is in place through the hole, seal gaps round it with a sand and cement mix.

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