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)
The obvious risk with a copper pipe lamp is that, somehow, the live wire gets in contact with the copper pipe. If someone then touched the pipe, they could have a serious shock. Because copper is conductive, it’s inherently more risky than making a lamp out of non-conductive material, so we have to be more careful to ensure this doesn’t happen.
The lamp could get live in two ways: either the cable could be pulled out of the bulb holder, or the flex could become damaged inside the pipe.
To reduce the risk of these happening, we’ll make sure that the cable is secured at the point it exits the lamp, so tugging on the cord doesn’t put force on the connection between the flex and the bulb holder, 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 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 onto the joint with the olive between. As the two parts are forced together, there’s enough pressure on the olive to deform it and create a solid joint. These are bulkier and this affects the look of the lamp, but they have two advantages: they don’t require a blow-torch, and they can be done after the flex is threaded through the lamp, so there’s not a problem creating complex shapes.
There are a couple of other options that would join the pipes together but that we can’t recommend. There are plastic pressure-fit connectors and you can secure the solderable joints with glue rather than solder. The reason we can’t recommend these is because they don’t make electrically conductive joints. This means that you can’t easily earth the entire metal body of the lamp, so if the live cable frayed in an unearthed part of the lamp, you could have a dangerous object.
You can bend copper pipes to create interesting shapes. The challenge is to create a bend without the pipe collapsing, and there are a few tools out there for the job, but that’s beyond the scope of this article.
Get inspired
You can get creative with the design – the only restriction is that you can actually thread the flex through the design.
We’ve gone for a three-pointed base, for the simple reason that three legs can’t wobble, but four or more can. Copper is a bit forgiving though. If you do opt for more legs and there’s a little wobble, you can bend copper slightly by hand to correct any misalignment.
Above this, we’ve got a vertical pipe with two 90 degree bends that end up hanging the bulb down. Originally, we had both of these corners as soldered joints, but we couldn’t thread the flex, so we had to cut one out and replace it with a compression joint. We could have replaced either one, but elected to do the outside one. We’ve also got a compression T-joint on the upright which gives us a place for our cable to escape.
The exact measurements don’t have to be precise – ours is about 30 cm high and 20 cm wide, but we didn’t even use a tape-measure, and just cut it by eye where it looked about right. It’s useful to have a bulb with you when cutting the lengths out so you can picture how it will look when it’s all fitted together.
Typically, bulb holders end in a 10 mm thread, and you’ll also need a pipe end stop with a 10 mm threaded hole that you can attach to the end of your lamp. You can join these two fittings with a 10 mm hollow threaded rod, and through this the cable will get from the bulb holder into the body of the lamp. All these bits you can get from a lamp maker store such as lampspares.co.uk.
Make sure that your bulb holder is either metal and earthed (which will earth the whole lamp provided all the joints are conductive), or you find another way to safely earth your lamp body.
At the other end, the flex needs to be secured as it leaves the pipe. Again, we’ll use a 10 mm threaded end stop, but this time we’ll need a cord gripper with a 10 mm thread. These are most commonly used to secure lamps hanging by their cord from the ceiling, but also work to secure the flex in this case. An alternative option is to use a rubber grommet to protect the flex, and add a flex strain relief to prevent the cable pulling through this hole. We found that this doesn’t fit in a 15 mm pipe, but you might be able to use this method if you’re using thicker pipe.
That’s all the pieces you’ll need – let’s put it all together. First, solder any joints you’ll be soldering, then thread the flex through all the parts, including compression joints. Join everything together and wire up the bulb holder and plug, according to the manufacturer’s instructions. This could be an easy build or it could be complex – it completely comes down to your design.
We’re basically there now, but there’s a couple of safety checks before getting started. If you’ve got a PAT tester, then this is ideal, but if not, we can check some things with a multimeter. First, check that the lamp’s properly earthed by ensuring that the resistance between the earth pin on the plug and any exposed metal is low enough (less than a few ohms). Secondly, make sure that the resistance between the live and earth pins is very, very high (this ensures that there’s not a leakage already). Remember that, just because your lamp is properly assembled now, it is no guarantee that it will remain that way, and you can repeat this test if you’re ever unsure about the safety of the lamp.
That’s all there is to it. Your lamp is now ready for use.
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.
