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Author Topic: custom made carbon filament  (Read 17403 times)

Offline marcin

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custom made carbon filament
« on: December 01, 2011, 03:19:28 pm »
Hi All

This is my first post. I am an electronics hobbyist and a vacuum tube collector. During the day I am a computational biologist currently living and working in Norway.
My current Id?e fixe is recreation of the original Fleming diode. One looking just like this. The problem with this tube is that it uses a carbon filament.
I am asking The Wisdom of This Forum for help on how to get such a filament. The filament is horseshoe shaped, approx. 25mm tall, 8-10mm wide and runs on approx. 12V (neither of these values are very critical).
I looked the Internet up and down and found that basically I have two options: Either I scavenge filament from those new-made carbon filament lamps and trim it down, or I make my own from scratch. Scavenging of course seems simpler. But if I learned anything in my life is that the simple way seldom works. ;)
Creating one from scratch would require a lot of effort: creating cellulose filament, likely by squirting, carbonizing it, and then flushing. Especially flushing seems tricky as it looks that it should be done in atmosphere of hydrocarbons and hydrogen. Still I believe it is doable. And of course there remains a small task of gluing a carbon filament to the metal lead wires.

Could anybody offer any opinion, suggestion or know-how?
Thanks,
  Marcin