11

FORGE

and this will also reduce the movement of the flex
inside the lamp, which will also minimise the risk of
it being damaged inside the lamp.
To mitigate the risk, should the flex insulation
somehow fail, we’ll ensure that the whole body of
the lamp is earthed. This means that if there is a
contact between the live part and the body of the
lamp, it’ll get harmlessly diverted to ground, and this
should either blow a fuse or trip a circuit breaker.
We’ll look at how to put these two protections in
place as we build the lamp.

SNIP SNIP
Copper pipes are soft and easy to work with. You
can get specialist pipe cutters, but most metal saws

YOU’LL NEED

15 mm copper

pipe (about 1 metre)

Earthed

bulb holder

Assorted pipe

joints (elbow and ‘T’)

2 × pipe end

stop, with M10

threaded holes

Hollow M10

threaded rod

(about 30 mm long)

M10 cord gripper

3 m of flex

Plug

Blow-torch

(optional)

In-line dimmer

(optional)

Left

Our copper pipe

ready for assembly.

Getting the cuts as

smooth as possible

will help make

sure everything fits

together properly

SWITCHES AND DIMMERS

Our bulb holder has an integrated switch, but there

are a few other options. You can have a torpedo

switch on the flex cable (just make sure that your

switch has earth pass-through, so the effort to

protect your lamp isn’t wasted).

Edison-style filament bulbs look particularly

good with the copper, and these dim particularly

well. You can get in-line dimmers that can be wired

into the flex, just as a torpedo switch could be. We

find the orange-red light of a dimmed filament bulb

very soothing in the evening.

will make short work of it. Whichever you use, you

need to make sure that the cuts are clean before

assembling your lamp. If there are any burrs, they

could stop the joints fitting together, or they could

dig into the cable, which could have disastrous

consequences. You’ll need a file that fits inside

the pipe, and give it a good scrubbing until there’s

nothing protruding from the cut.

Let’s take a look at our options for joining the

pipe together. The most elegant method is to use

soldered joints. These are pre-formed joints and

bends that slot around the pipe and can be heated

and soldered together. Some already contain solder,

while others need to have solder added. Whichever

version you use, you need to add flux to the pipes

first to ensure a good joint. They should fit quite

snugly, so you can push the pipes into place and line

everything up, then go around with a blow-torch and

solder every joint. The big disadvantage of these

joints is that you have to seal them without the cable

inside, and this makes it hard to thread the cable

through more complex shapes. We found that we

could thread the flex round a 90 degree bend, but

any more than this proved challenging.

The second joint option is compression joints.

These work by having three parts: the joint itself that

you press the pipes into, then an olive that looks like

a ring of brass or copper, and finally a threaded end.

These work by screwing the threaded end