Working with copper pipe

Copper is now the most widely used material for pipework. And unlike the old lead pipes which preceded it, copper pipe is quite easy to work with. Once you know how to cut, bend and join it, a whole host of home improvement projects become possible.

Although expensive, the choice of copper as a piping material is a natural one. It does not rust, it is suitable for both hot and cold water systems and it is soft enough to work with in tight corners. Plastics piping is gaining in popularity but has not, as yet, replaced copper – systems capable of dealing with hot water are a relatively new development.

The sizes of copper pipe used in domestic plumbing have gradually become standardized – typically 22mm for the rising main and for certain low-pressure installations, and 15mm for the pipe used to supply outlets such as sink and basin taps or washing machines. But in older installations, imperial measurements are still found.

Although any new pipe or fitting you buy will be metric, the existing pipe-work to which it is being joined may be in an imperial size – especially in an older house. Joining the two is not difficult, but you must be aware of the difference and allow for it.

In most instances, incorporation of further copper plumbing within an existing system presents few problems. But if joints have to be made to old lead or iron piping be wary: unless you already have some practical plumbing experience, seek the advice of a plumber (working with lead pipe is covered further on in the course). Normally, this would apply only to those modernizing the plumbing of older houses. Nearly all modern domestic plumbing installations are based on the use of copper, stainless-steel or plastics piping.


Few specialist items of equipment are really necessary for the more straightforward plumbing jobs such as cutting pipe and making simple types of join. Most of the items can be found in every handyman’s toolbox – you need a good quality hacksaw with medium-fine blade, a flexible steel 2m rule, wrenches, adjustable spanners, files, and steel wool.

It is often possible to get round the need for making your own bends by planning the pipe run in advance and by a careful choice of the available fittings.

In the UK, alterations to existing plumbing installations are strictly controlled by local Water Authority bye-laws. Because of this, you should inform your local water board of your plans at least seven days before work starts. As well as giving practical advice, they will warn you against any possible infringement of their regulations. In Australia alterations to the plumbing system must be carried out by a qualified plumber to comply with Australian law.

Pipe bending is not a particularly difficult skill, but usually requires use of a blowlamp for best results – this is a subject covered in the next stage of the plumbing course. Ready-made bend sections – or fittings – can be used instead but are expensive on all but a short pipe run.

Measuring and cutting

The first task is to estimate the amount of pipe required for your project. This can be done by using scale plans you have prepared or better, from direct measurement of the run using a flexible steel tape. For really tricky pipe runs, use a piece of wire instead of the tape – feed it along the route first, then measure its length. As purpose-made fittings permit much sharper bends than bend sections consider using these.

Cutting copper pipe

At its simplest, cutting copper pipe requires only a straight eye, a firm grip and a hacksaw. But in order to avoid problems later on, you should make sure that each cut is as clean and as straight as possible. Take particular care in finishing a cut.

If a great deal of cutting has to be done, consider investing in, or hiring, a pipe cutter. It is recommended for use only on the thickest-walled piping as there is some tendency for the cutting area to be crimped if thin pipe is being cut. This might impede water flow later, resulting in noise-inducing turbulence within the pipe.

First, using a fine-toothed flat file, straighten and smooth out the cut edge. Any ragged edges that are left will probably cause leaks later on, so if you cannot get a good finish, leave it and cut the pipe again.

Next remove any swarf (metal shavings) from the outside rim and clean up the inside surface with a round file.

As the edge becomes smooth, angle your file so that you bevel the pipe end slightly. Finally, thoroughly clean the finished pipe end with steel wool or a wire brush.

To avoid wastage – and the possibility of mis-measuring – cut and finish one length of pipe before you measure and cut the next.

Joining the pipe

Copper pipe can either be joined with screw fittings or with soldered joints. Soldered joints are cheaper and have a neater appearance, but they can only be used once the techniques of using a blowlamp have been mastered.

Screw fittings are much easier to use and you are unlikely to need many for a simple pipe run.

The two types of screw, or compression fittings used in plumbing are known as manipulative and non-manipulative. The former, which require special tools to flare the pipe ends are rarely used in DIY work. Non-manipulative compression joints are more complicated, but form a good seal once they are assembled. And because they can be taken apart with ease, they also allow you much more flexibility.

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