18 May 2010

How to Hollow a G40 Lightbulb (photograph tutorial)

Greetings, ladies and gentlemen.  Today we explore the mechanics of hollowing out a G40 lightbulb.  First you get your tools.  My favorite three are a small screwdriver, pliers, and a pocket knife. You will need sandpaper or steel wool for the last steps.
It is also advised you use gloves.  I forgot to use them for most of the pictures.  Don't follow my bad example.
 Since I do this all the time, I have used a plastic bin for all the lightbulb guts and broken glass.  The towel is to help decrease the spread of glass, should it spill onto the floor.

The first thing you do is peel that copper plating off with the pliers.  Simple enough.

I forgot to take a picture of the black glass underneath the plating being broken, but it's quite all right.  This is what the lightbulb looks like minus the copper plating and black glass (it is actually kind of purple...)

I use my pliers to bend the metal edge on the inside back against the inside of the base so it will not cut anyone (especially if this is to be used for a fish!)

This is the part where I break the glass tube you saw two pictures ago with the wire.  It releases the pressure and argon gas (harmless, no worries) and makes the lightbulb a lot less likely to break from here on out.  After the tube is broken, I disconnect the two wires on the inside and poke the glass where the tube was.  Eventually I have broken most of the glass and it looks something like this:

Looks pretty rough, eh?

 Poke it some more, then start smoothing it with the knife.  Can't have any sharp edges!

 Maybe you shouldn't do this part... But I have to be positive that the inside is not going to cut a fish or you, so I feel around the inside where I just smoothed the glass to make sure it's all good.

Looks pretty good!

Introducing... lightbulb guts!  These are shaken out of the lightbulb into my plastic bin.

 See that?  That's solder.  Someone did a terrible looking job, too.  Well, this has the chance of having lead in it, so it's gotta go.

I remembered my gloves at this point.. 
Basically, pry the solder off.  Be careful with that knife, though.  If it slips, you might not have a finger anymore.  USE GLOVES.

 Time for the steel wool!  It looks nasty where the solder was if you don't use it.  Kind of a burnt look.

 This has got to go too.  Use the steel wool, but gently.  Don't be scared of a few hardly visible scratches.  It looks better than this stamp, I think.

 You should be done now!  Congratulations!  A hollow lightbulb.  Great for a number of uses.

 Yeah, sometimes they break.  It's all right.  It happens.  (this was the second lightbulb I hollowed that day)

I often turn these into fishbowls.  They're a perfect size for a female betta (a small male betta works too!)  If it becomes one of my fish's homes, I usually will stick a bit of bamboo or rooted plant in there as well.  The fishes like to swim about in the root systems, and it keeps the lightbulb clean so I don't have to change the water as often.  Plants love ammonia, interestingly, and will thrive on the waste of the fish, including any uneaten food.  Works out great!  Kind of like a mini ecosystem...

If you are interested in seeing this fishbowl actually being used as such, I have some for sale here.


  1. Nice going
    thank you for this tutorial!
    Green kisses

  2. very cool process, your so creative!!!