Copper Cactus Vacuum Tube LED Lamp

Copper is seriously under-rated as a decorative material. Nothing else has such a warm quality metallic look, so it's a natural for candlesticks and lamps. Some of you probably also remember when the warm amber glow of the vacuum tube was king.

This design combines many ideas that will appeal to those who love the Southwest - since it's shaped like a saguaro cactus - as well as steampunk/diesel-punk aficionados. Plus, instead of using the hot, power-hungry filaments of the vacuum tubes, it lights the tubes from below with cool-running LEDs, which in this design use about two watts of power and will probably last a lifetime!

And, just in case warm amber isn't your thing, a remote control that allows color and brightness changes and cool rainbow effects!

This lamp is not hard to build, thanks to the wide availability of multi-color LED strips that run on a safe 12 volts. All it takes is some basic soldering skills and a little patience to get a truly unique accent lamp.

Don't want to build one? You can get one in my Etsy store right now!

My finished lamp stands about 15" high. To build it as pictured, you'll need about 2 feet of 3/4" copper pipe from your friendly local home improvement store, and as long as you're there, get the following:

• 2- 3/4" copper elbows to fit above pipe
• 2- 3/4" copper Tees
• A tubing cutter, hacksaw or other means to cut the pipe, if you don't already have one.
• Some wood for the base. I used 1/4" MDF with a walnut veneer, but you can use almost anything that can have a 7/8" (.875") hole drilled into it and be large enough - and thick enough - to be stable. It also needs to be hollow so the wiring and control unit can be tucked inside.
• Any tools you might need to cut the base material to size, including a 7/8" drill bit for the center hole.
• Glue or fasteners for assembling the base.
• Epoxy to assemble the copper parts.

The copper parts will set you back around $20.

Once you come home with your bag of parts from H**e D***t or L**es, Gloat over your lovely copper, peel off those %$#!#^$ price labels, shine the parts up with some steel wool if you want, and then head over to eBay or Amazon for your electrical parts:

• 12 volt RGB (Not the programmable kind) LED strip: these can be cut with scissors every 3 LEDs and will work directly from 12 volts without needing any extra resistors. You can also find sets containing the LED strip, controller, and power supply all in one package.
• 12 volt power cord with 5.5mm barrel plug. This plug size has become almost a standard and is the easiest to find.
• RGB LED strip controller. These come in many, many varieties; I used the 11 key RF (Radio frequency) version. RF means as long as the base is non-metallic, I don't need to drill any holes for the sensor. It's also very compact and already has a power jack which fits the power cord above.
• RGB wire. 4-conductor wire to connect the LEDs. You'll only need about 5 feet.
• RGB connector. Gives an easy way to connect the three lights to the controller.
• And, of course, vacuum tubes. They don't need to be in working order, they just need a clear glass (not black Bakelite) base and be the right diameter (3/4") to fit inside the pipe. I used these from Etsy.

You'll also need a soldering iron, solder, wire cutters/strippers, a file or sandpaper for deburring the pipe, and basic soldering skills.

Get out your tubing cutter or hacksaw and cut your copper pipe to the following lengths:

• 1-6"
• 1-4"
• 1-3"
• 1-2.5"
• 3-1.5"

De-burr the inside and outside of each piece. Pay particular attention to one end of the 4", 3", and 2.5" pieces, since those ends will be visible in the finished product. Make sure those ends are completely deburred, or at least enough to fit the vacuum tubes without any force. The insides of the other ends need to be deburred enough to eliminate any sharp edges that might cut into the wiring.

Test-assemble the whole thing and leave it for the next step. Do not glue anything at this time.

The reason we didn't glue the pipes together yet is that it's much easier to thread the wiring through the pipes one piece at a time.

The LED strip has markings on it where it's safe to cut. Just use scissors to cut off three strips of three each. The solder pads at the cut ends are marked with the colors they control: Red, Green, and Blue, plus Black (probably marked + (plus sign) on the solder pad), which is the common wire for all three colors.

Working from your temporary pipe assembly, cut three pieces of your RGB wire to a length that will extend from the top, through each branch, plus about 4" extra at the bottom. Strip about 1/8" from each wire on one end.

The easiest way to solder the wire to the LED strip is to fasten the strip down to your workbench with a strip of tape and "tin" the solder pads first. Also tin the wire ends. Once you've done that, it's a simple matter to just reheat the solder on the pad, place the tinned wire on the correct pad, and hold it as still as you can for the 2 or 3 seconds it takes the solder to cool. Repeat this with the other three wires, matching the wire colors to the R, G, and B marks on the strip, and solder the leftover wire (Black on my wire) to the + or common pad.

Make the other two assemblies the same way. Insulate the solder pads by wrapping a couple of turns of tape around them, or better yet, a piece of heat shrink tubing. Remember, copper is a conductor of electricity, so you need to be careful to avoid shorts.

You can glue a 1.5" pipe piece into each elbow and into one of the tees at this time. These are sized such that the tees and elbows are butted against each other when correctly assembled. Refer to the exploded diagram for position. I recommend 5-minute epoxy because it gives you some working time and is easy to clean up with rubbing alcohol.

Now, disassemble your temporary pipe assembly and thread the wires through the branches from the top, through the elbow, then the tee, and out the bottom. Thread the center wire straight through. Be gentle with the wires, especially if you didn't do such a good deburring job. You don't want to scrape insulation off the wires on those sharp edges. There is no risk of shock, but you do want this to work!

Gently curve each of the LED strips into a "U" shape (Don't kink it!) and slide into the tops of the pipes with the center LED facing up. At this point, you can tack the strips in place with a bit of hot glue, although they'll probably stay put without gluing.

Strip around 1/2" from each of the wires coming out of the bottom. Get your RGB connector, and strip it's wires the same way. Take all 4 of the same color wires and twist them together; you should wind up with 4 black, 4 red, etc., twisted together. Solder these connections and insulate them with tape or heat shrink tubing.

I cannot overemphasize the need for thorough testing before buttoning up this project!

There is no heartbreak greater than spending hours on a project, gluing it shut so you can't get back into it, then finding out it doesn't work. As a matter of fact, it's not a bad idea to test your strip and controller together before even starting assembly.

Plug your RGB connector into the RGB controller. You'll see a small mark of some sort on the connectors (often a triangle or arrow). Those marks should be matched to each other; if you plug it in backwards, nothing will happen. Plug your 12 volt power cord into the controller and a wall outlet. If the LEDs don't come on, don't panic! Try pressing the "On" button on the remote control (Some of these Chinese RGB controllers don't come with a remote control battery; check that, too). If that doesn't work, try unplugging the LED connector and reversing it. If only one strip fails to light, look for a bad solder connection on the (+) wire for that strip. If only one color fails to light, look for a bad connection for that color. It's also possible you got a bad controller, although that's rare.

Do not proceed until everything is working.

Now, you should have a bunch of separate pipe parts laid out on your table with wire running through them. Beginning at the top, epoxy the parts together. The neatest way to do this is place the epoxy inside the tee or elbow, insert the pipe, and twist back and forth about 90 degrees to spread it around. You can wipe up any spills with a bit of rubbing alcohol (Dirt cheap at your local drugstore, and a great mild solvent). The short pipe pieces are the right length to allow the elbows and tees to butt up against each other.

As you glue the parts together, you can gently "milk" the wire down through the assembly so that when you're done, the top LEDs in the strips are about 1/2" below the top of the pipes.

Adjust position to your taste (I just laid it flat on my bench) and put the assembly aside until the epoxy sets.

I made my base 4.5" square and 1" deep, having determined experimentally that it was a good size for stability (I tried to tip it over). The base is 1/4" MDF cut on a laser, just because I had access to one; it would be almost as easy to make it with ordinary woodworking tools.

If you're using the suggested RF module, don't use a metal base or the remote won't work. If you use an IR (infrared) module instead, you can make the base out of anything, but you'll need a hole for the sensor.

The assembly in the center is to add some stability by stacking up four 1/4" pieces, the top two of which have a 7/8" hole in the center, and the bottom two have a slot that's a little smaller. This means the pipe can go 3/4" into the base, so there will be no wobble. The slot is to allow room for the wires, as shown in the assembled view above.

Two suggested patterns for the base are available for download below. The "simple" base is easiest to make with simple tools.

The hole for the power cord is .450" to make the connector from the RGB controller a snug fit. The reason for the "ears" on the center parts is to give a backing for the power jack so it's not just being held in by glue. You can see the tight fit of the jack against the center part. The "R" on the center parts goes towards the rear of the base.

Assemble the sides of the base first, set the top on the sides, clamp if needed, and let dry. If you pre-drilled or laser-cut the center parts, stack them on the underside, with your scrap of copper pipe through the holes to keep them lined up till the glue sets. Be sure to pull it out as soon as you can so you don't glue the scrap pipe into the base!

If you plan to drill the holes, stack up the first two center parts and let glue dry overnight, the drill through all 3 parts at once (preferably with a drill press) before adding the 2 slotted pieces.

Paint, veneer, or finish your base to taste, push the cactus into the hole (it should be snug enough to not need glue), position the power jack in it's hole, and glue everything down with hot glue. You're almost done! Glue some felt on the bottom if you want (After testing again!).

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Be sure to handle the tubes gently; they are made of thin glass.

There are several options for mounting the tubes, the easiest being just glue 'em in. I decided to make the mounting a little more professional by making a "socket" out of a scrap of 1/4" clear acrylic (plexiglass). This piece is sized to be a snug fit in the top of the pipe. The pattern is attached. I glued it in far enough down so the tube has some support, and added a shim around the top of the pipe to keep the tube from wobbling. My shim was another piece of acrylic, but a band of hot glue or a rubber band would probably do as well. The finished product is stable, and since the plastic socket holds the tube reasonably firmly, I saw no need to glue in the tubes.

And there you have it. The most unique lamp I've ever seen!

Other ideas: If tubes aren't your bag, and you don't need a million colors, those strings of LED Edison lamps in the Christmas department would work well, too. If you get a string of 25 and take it apart, three of those in series will work fine on 12 volts. You can also use regular 12 volt LEDs and glass or plastic test tubes.

The lamp can also be made in any other shape achievable with copper pipe. RGB Menorah, anyone?

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