Vacuum Tube LED Candle




Introduction: Vacuum Tube LED Candle

About: I've always liked pulling things apart - it's the putting back together again that I have some issues with.

Vacuum Tubes are an amazing thing to behold. They look like miniature works of art made by a mad scientist! I recently came to own some used vacuum tubes which were no longer functional. Instead of sticking them into a draw or god forbid – throw them away, I decided to work on ways to display them.

For this ible’ I decided to mount one in a block of wood and add a flickering LED. You could just mount the tube into the wood without the LED but I wanted to give it a little life. As the block of wood is solid you will need to carve out a recess for the battery and switch. This isn’t too hard as long as you have some chisels.

Step 1: Parts and Tools


1. Vacuum tube. – eBay

2. Wood. Any old piece of wood as long as it has some character

3. 2 X AA Battery holder - eBay

4. 2 X AA Batteries

5. Wires

6. Switch – eBay. I used quite a large switch which was more time consuming to add. It would be simpler to add a smaller toggle switch – leave it up to you though.

7. Brass strip – eBay

8. Flickering LED - eBay


1. Drill

2. Sander

3. Soldering iron

4. Pliers

5. Chisels

6. Vice

7. Double sided tape

8. Oscillating multi tool

Step 2: Prepare the Wood


1. Choose your wood. I used a piece of drift wood I found at the beach some time ago.

2. As I was using an old piece of wood, I had to sand it back which revealed some beautiful wood underneath the weathered surface

3. Cut to the size that you want to make the stand. Remember you need to add the switch as well so don’t make it too small.

Step 3: Making the Battery Section - Marking

Once you have the wood sanded and prepared, you next need to mark out the area that you need to cut out for the battery holder.


1. Place the block of wood into a vice to hold it steady

2. Place the battery holder onto the wood and trace around

3. To make the initial cuts I used an oscillating multi tool which you can see an image of below. I found that this made the job of removing the battery section very easy.

Step 4: Making the Battery Section - Chisling


1. Grab a chisel and start to remove the marked section. I used a large head chisel and carefully removed the wood.

2. Check your work by placing the battery holder into the battery section and seeing how it fits

3. Keep removing the wood until the battery holder fits into the hole. Make sure you have about 5mm of wood over the battery holder.

Step 5: Making the Mounting Hole for the Vacuum Tube


1. To make the perfect sized hole, I used a 19mm wood boring drill bit. These are also known as flat or spade drill bits and they look like the one in the image below.

2. Find the centre of the wood and start to drill. The hole can go right through to the other hole you made for the battery as it won’t affect the way the vacuum tube sits in the wood.

3. Once drilled, test to make sure the tube sits well in the hole. You shouldn’t have to glue it into place as the fit is nice and snug.

Step 6: Adding a Switch

I added quite a large switch but you could easily add a smaller toggle switch if you wanted to. Also, I added a piece of brass to cover up any holes made in the wood


1. First mark out the size of the switch onto the wood

2. Next, use a drill to remove most of the wood. You will need to drill right through the wood

3. Grab a small chisel and start to remove the wood in the inside of the hole. Be careful though not to chip the sides. If you do, grab some super glue and stick it back on. You can sand it back later.

4. Keep on trying the switch until it fits into the hole made

5. Add some wires to the terminals on the switch

6. Drill a small hole from the battery compartment through to the switch hole. Pass the wires from the switch through the hole and into the battery compartment.

7. Push the switch into place

8. Cut a strip of bass so it is big enough to cover the hole and drill a hole in the middle for the switch.

9. Place the brass over the switch and add some super glue to the bottom of the brass and secure into place.

Step 7: Add the Batteries


1. Solder one of the battery wires to the switch wire and add a little bit of heat shrink.

2. Thread the other wire from the switch and the battery through the hole in the top of the wood

3. Secure the batteries into place with some good quality double sided tape. I use the foam type tape as it works the best.

Step 8: Add Some Wax

To bring out the grain in the wood, I added some bees wax.


1. With a clean cloth, rub some wax all over the wood. Make sure you rub it in well and get it into all of the grain of the wood

2. Wipe off the excess wax with another rag.

Step 9: Add the LED


1. Trim the LED’s legs.

2. Next, add some solder to the legs and the wires coming out the top hole. Before you solder the LED into place, test to make sure you have the correct polarities on the LED.

3. Solder the LED into place and don’t forget to add some heat shrink.

4. Test

Step 10: Adding the Vacuum Tube


1. First you will need to remove the middle section of the vacuum tube. This is a plastic part which has a glass cylinder down the middle.

2. Place the tube into a vice (obviously not the glass section, just the plastic base) and with a pair of wire cutters, start to chip away at the plastic

3. Remove all of the plastic until it is flush with the base

4. Give the tube a shake to remove any broken glass inside.

5. Push the LED inside the hole. There shouldn’t be any need to hot glue it into place

6. Push the vacuum tube into the hole in the top of the wood. The legs on the tube will hold it into place.

7. You might need to work out the best position for the LED so if you find it isn’t in the correct position, pull it out and try again.

Step 11:

That’s it!

Hopefully you have a very cool looking vacuum tube and stand. The soft glow of the flickering candle helps bring this marvel of electronics back to life.

Next I’m thinking of making a display stand for a whole bunch of different types of vacuum tubes.

Thanks for checking it out and happy making



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    28 Discussions

    Just LOVE this idea. So many non-functioning tubes are out there. People throw them out or give them away. And I hate to see them in the trash. Well done.

    Most vacuum tubes glow when the heater filament is energized and a great many use 6.3 v for the heater circuit. With not too much trouble you could design a 6.3 v power supply and plug it into the wall. It wouldn't flicker, but it would have an authentic glow! Most of the old tubes I have laying around failed for reasons other than the heater circuit anyhow.

    5 replies

    Thanks for the heads-up. I tested this last night on a couple and got a few to glow. They looked fantastic (and hot!). I tried 6v's and also 9v's and both worked ok (got more light out of the 9v but also more heat).

    Seems I couldn’t respond via the link that your response provided.
    I will be very interested in hearing how your joule thief tests go. Your results will depend on the quality of the circuit you build but it will be better than not having one at all since two AA batteries (3vdc Max) discharged to <1v is close to the best you’ll see going cold turkey. The thief should be able to get you down to <.3 depending on the semiconductors you use but it’ll be good whatever you do. Please do let me know.

    Your idea of a simple modular plug-in power supply is great. That will solve all the power requirement problems and be very simple to implement.

    I posted another comment (or attempted to) but it doesn’t look like it made it.

    Someone suggested you excite the tube filament for lighting but I’m wondering how well that will work. The filament is a heater and is designed to be energized in order to create the excess electrons required for the tube to operate as designed. As a heater that implies current, maybe a bunch, even close to an amp depending on the tube. Not necessarily a great approach unless you just want to enjoy the tube’s natural glow and you are not concerned about energy consumption nor heat. Either way it’s totally cool. Please let me know what else you might do with this project. I think it is so cool!

    Another thing is to build a little joule thief curcuit. It will increase the battery life. There’s a bunch of simple ones around. Essentially it’s a switching power supply that allows you to us the voltage available below the cutoff of the led which is about .6V. You can take it wayyyy down.

    I'm going to do a few tests and see how I can maybe rig up one with a joule thief and a few AA batteries. It will be interesting to see how long the tube glows for.

    Another way would be just to use a 6v / 9v wall adapter.

    Not to mention the filament is indeed a heater which generates the excess electrons needed for tube operation. Heater implies current so the filament would not just create heat but use considerable power as well.

    Looks really cool. You inspired me to make this! Parts ordered.

    2 replies

    Very clever. Ideal for a child's room. Ideal for mine, too!

    1 reply

    11 months ago

    Wonderful idea to use an old tube as a lamp

    1 reply

    Hi lonesoulsurfer

    Pretty nice litte thing!

    I love this flickering tubes!

    Thanks for sharing and now I am stepping down to my workshop looking for the right tubes.....;-))

    Yours Aeon Junophor

    1 reply

    Hey Aeon,
    Thanks very much! Those flickering LED's are damn cool.


    11 months ago

    I was wondering how long the batteries would last. What if a joule thief was added. I'm just guessing here, I haven't researched it yet. Just getting an opinion.

    1 reply

    LED's are very efficient and only draw a minimal amount of milliamps so I reckon you would get at least 20 hours or more out of the batteries. You can buy LED candles which use a button cell 3v battery and those last for ages so with 2 X AA, you'd have plenty of power to run them for ages.