When I was growing up I had a keen interest in the sciences. Mostly because of the cool gear that scientists used, you know, beakers, flasks, Bunsen burners that sort of thing. Well, not only did I not have the money for those sorts of thing but I had no idea where to even buy them if I could. So I had to improvise. One of the better improvisations I was able to do was to hollow out a light bulb and use it for other things. The glass that makes the envelope of the build is quite heat resistant and the screw base is good to attach things to (even better if you can find old ones with brass bases, you can solder to those). I made a number of small boilers in order to learn about steam and distillation. I hope to show people that even if a bulb burns out, it can still be useful.
You will need some common tools, a screwdriver (regular) and snips (or needle nose pliers). Use whatever bulb you have handy. *CAUTION* Never use a fluorescent bulb for this project, no matter how cool it looks. The powder used to coat the inside of them is made from phosphor and is quite toxic. You’re also working with glass, so use eye protection! You can’t see mine because I’m wearing them. You should also use gloves or wrap the bulb in a towel just in case it breaks. Yeah, you can’t see mine because i didn’t have any handy. So do as I say and not as I do, got it?
First, grip the little solder point and give it a good twist. You will free the brass contact and break one of the wires leading to the filament.
Once the contact has been pulled out, carefully crack the glass insulator. The chips from this are quite pervasive, they get into just about anything in the area and they are razor sharp. Use caution.
After the insulator has been removed you can see the inside supports of the filament and the fill hole. In the old days bulbs were evacuated of atmosphere to keep the filament from oxidising and burning through. Now days the glass envelope is back filled with an inert gas like argon. The keeps the filament from burning through and makes the bulbs safer.
Use the screwdriver to break the fill tube.
The fill tube could be saved for a later project if you wish.
You can now shake the filament assembly out of the tube. If the tungsten wire is still intact you could probably find a good use for it. You could make another light bulb if your stuck for something to do I suppose.
The bulb needs a good cleaning. This powder, as far as I can tell, is somewhat safe. You should still be careful and keep it away from your mouth and anything you might eat near.
Mind the sharp bits of glass in the socket when doing this. If you have some stubborn bits inside of it that you can’t get to with this technique you can fill the bulb with a little salt and shake it about. this should scour the powder off the walls.
There you are, an empty light bulb ready for a new lease on life.
As an example I built this neo-Victorian New Age Flemming like valve out of a discarded bulb.
A more traditional use is as a vessel to boil water. I wouldn’t use too hot of a flame, a candle or an alcohol burner should be about as much heat as you should use. It is after all only a light bulb. Real lab ware is much thicker and can take more heat. Still, for the amateur experimenter this can be handy to have.
I hope you have enjoyed this little project and have fun making useful things out of what was once junk.