Popular Sciences How2.0 column has a great article this week on how to create a light bulb in your own garage. Well, if you have some tungesten wire, helium, and an old arc welder lying about that is.
Popular Science: I used helium because it’s easily available and lighter than air, allowing me to fill my bulb, an upside-down glass ice bucket (wedding present, I believe), from the bottom. The helium floated up, displacing the air inside. With a steady stream flowing in, I didn’t even need to seal the bucket very well???I just wrapped a sheet of tinfoil over the bottom to keep eddies of air from wafting in.
For a filament, I used a thick tungsten wire I had lying around the shop and, for the power supply, a small stick welder I got at an auction. It supplied about 50 amps at 30 volts, giving me a 1,500-watt bulb. When I powered up the filament without the bucket in place, it produced a prodigious quantity of tungsten-oxide smoke and didn’t last very long. But with the bucket on and a steady flow of helium, the filament glowed brightly and cleanly.