Giant Fake Vacuum Tube

I found this large glass cover, or dome at a thrift store on sale for a dollar, and the minute I saw it I knew that I wanted to make a monster fake vacuum tube.

I used E-wire to make up the glowing cathode element. I am sure that different colours, patterns, or alpha numeric characters could be used in the display.

I managed to fool my father, from a couple of feet, that it was a real vacuum tube. He had worked with tubes when he was a young man, and at first sight was shocked by the size of it.

The final tube is about 13 inches or 32cm (see D cell battery in picture for scale)

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Step 1:

You will need the following parts:

1 Glass dome (I think this came from a clock, and was Thrift store find at one dollar)
2 ABS Plumbing pipe coupler (four dollars at a hardware store)
3 Luminescent wire, EL wire , ( I bought this at Ikea for a few dollars)
4 Scraped computer hard drive and mounting rails (Free!)
5 Scrapped computer parts ( I used the screws, drive rails, stand offs and other scrapped bits, all free)
6 Black Arborite, or black painted, wood half an inch or 1.5 cm thick (Ikea for three dollars)
7 Large nails ( I used nine, six inch nails and cut the pointed ends off)

Hot glue

Things to consider:

Make sure you have your glass dome with you when you buy your pipe or pipe coupling.
You want a snug fit. I had to sand out the inside of the pipe to get the glass to just fit.
I wanted to be able to remove the dome, but you could glue it if you need to.

Step 2:

Trace out and cut a circle of black wood to fit inside the tube, you need one to fit inside and rest on the ledge that the pipe coupling has. This is where you will mount the tube elements.

The glass dome will rest on this circle of wood.

I mounted a hard drive platter on the center of this and all the various scrap bits of metal I had to make the inside of the tube and tested the dome fit each time I added an element.

Be creative, use Google to find tube images for reference. I used what scrap I had lying around.

Step 3:

Make the base for the nails (fake connectors) You could leave these off, or make a bigger socket to plug it into.

Trace an inside outline of your ABS pipe on your wood and cut out what will be the bottom and sand or file to get a nice snug fit.

Cut the pointed tips off your nails, and make them all the same length ( I used nine)

Drill well spaced holes in the wood, just big enough to admit the nails, and hot glue the nail heads to the wood on what will be the inside of the tube.

Once you have the wood inside the tube use some small screws on the edge to hold the tube to the wood base.

Step 4:

Luminescent wire, EL wire.

I used EL wire for the "Emitter" element for my tube.

This pictured EL wire unit from Ikea cost about $2.00 and can produce a constant light or flash on and off. The Ikea name for this was "Glansa" , but I am not sure if they still sell it. The Ikea unit runs on two AA batteries, and an external wall wart could be used to power it.

EL wire can be found all over the internet and goes by Luminescent wire, or EL wire try

I just hung the EL wire over some rods taken from a scrap cd drive, but I am sure that you could make characters, logos, etc. and maybe make a large fake nixie tube, as there is easily enough space inside the tube for a micro-controller.

I drilled some holes to thread the wire into the space between the top and base.

Step 5:

The final product, side view.

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    33 Discussions


    3 years ago

    Imitate getter on top with paint.


    8 years ago on Introduction

    This is really awesome. I am a fan of mini and giant sized stuff, such as the giant keyboard key barstools on here. This is just really neat though, especially the hard drive stuff you used.


    8 years ago on Introduction

    I would have used several pieces of EL wire, each in the shape of a different number, and connected them with regular wire to the nails and made a giant working NIXIE TUBE!

    1 reply

    Reply 10 years ago on Introduction

    It may be possible to make the entire thing, or something like it, into plasma dome. Then it would be a really neat paper weight.


    8 years ago on Introduction

    What about making numbers with the EL wire instead of fake cathode? Paint it red and it will be nice.


    8 years ago on Introduction

    I think orange or amber EL wire will look better, because the filament on real tubes glows dull orange or amber.

    I bought some polycarbonate wine glasses to make some fake tubes for my steampunk projects.


    Reply 10 years ago on Introduction

    well the guy Alex mentioned blue that is normal but a red led makes it look like it's hot plating.


    10 years ago on Introduction

    Here are a couple pics of the one I made. If I get enough requests I will take it apart and post more. The one on the left is the tube in the dark (The wire is from cool neon it is the high bright) and the one on the right is the tube in the light.

    Vaccume Tube Dark.jpgVaccume Tube Light.jpg
    1 reply

    10 years ago on Introduction

    Your instructable... is the PERFECT example of why I love instructables, let me explain: I started off reading, thinking to myself "what POSSIBLE use could I have for this?" less than a minute later... ALL I can think about... is a giant nixie tube clock... 3 feet wide :) Your instructable is an inspiration! Thank you!

    1 reply

    Reply 10 years ago on Introduction


    It was one of those things that just had to be, maybe the clock has to be as well. Please post pictures if you make a clock I would love to see that.

    Check out this on EbayEbay You can get enough domes for your project at a reasonable price and all the same size. Hope that does not set off a bidding war!