With most of the equipment and tools we now take for granted and yet to be developed, the early pioneers of the electrical age had to carry a lot of work in addition to electrical skills. Machining, chemistry and metallurgy were all basic skills that the inventor had to have or hire. Most of these abilities still have some value, but one that was once crucial – glass blowing – has sadly fallen into relative obscurity.
There are still practitioners, of course, like [2SC1815] who is learning to make homemade incandescent light bulbs. The Instructable is in English and Japanese and the process is explained in detail. The base materials include soda-lime glass tubes and preloaded tungsten filaments. The support wires are made of Dumet, an alloy of iron, nickel and cobalt with an oxidized copper coating that forms a vacuum seal with molten glass. The filament is crimped to Dumet's cables and pinched in a glass tube. One bulb is blown into another piece of pipe and the two are welded together, evacuated with a vacuum pump and sealed. The bulbs are fired after sealing to eliminate residual water vapor. The resulting bulbs have a cheerful glow and a rustic look that we really like.
Of course, it is not a big leap from do-it-yourself light bulbs to create their own vacuum valves. that's how [Dalibor Farny] I started his craft business in Nixie, after all.