Originally Posted by MadMan
This is interesting actually. We really need to have a comprehensive source of information for making/rebuilding tubes... Enough of the knowledge has been lost already, it wont be long before it's all gone forever.
Nickel for a cathode seems easy enough, but is it plated with barium or like just painted on?
Nickel used for cathodes needed to be ultra-pure, as even tiny amounts of certain impurities (particularly silicon) would greatly reduce tube life in some applications.
The amount of chemistry and materials science that went into tube manufacture is quite amazing. It was nearly as complex as semiconductor fabrication is today. Entire industries sprung up (and died) to service the electron tube business.
The closest thing I have seen to a comprehensive book on making tubes is the 1962 RCA manual "Electron Tube Design". Available here: