[Big Bad Bob]

Peter Wieck suggested some videos, and I found others, that might he
helpful to anyone who might want to make tubes.

These two go over the needed equipment (poor audio quality though)

https://www.youtube.com/watch?v=3FN9J4zgsgk
https://www.youtube.com/watch?v=DeowhLVl7Hw

These show actually making tubes

https://www.youtube.com/watch?v=EzyXMEpq4qw
https://www.youtube.com/watch?v=5WCWejeRR_s


This wikipedia page discusses the glass to metal seal and various
materials that can be used to achieve a good one. This was only hinted
at in the Mullard video.

https://en.wikipedia.org/wiki/Glass-to-metal_seal


And this link is a web site for what is apparently the last small glass
tube maker in the USA, and the company is downsizing and selling off
equipment and other stuff (like prototype tubes).

http://vacuumtubefactory.com/


I'm pretty sure that tube-related tech is STILL valid for a lot of
things for which there is no (reasonable) solid state equivalent, and
it's not just microwave ovens, RF power stages, and nixie clocks, and
things of that mature. i've got ideas of my own, different ways to heat
a cathode that would allow for VERY high cathode potentials [as one
example] as opposed to using hundreds or even thousands of selenium
rectifier disks to build a giant stack (let's say 1,000,000 volts DC).
Done right, a glass envelope would not have to be several feet long nor
contain a bunch of transformers in series to insulate up to a megavolt.
And you'd be able to use these as a voltage multiplier [which could have
very wide potential swings].


As such we don't want to lose the skills needed to make them. I'm sure
there are even more uses that have not yet been discovered.


--
(aka 'Bombastic Bob' in case you wondered)

'Feeling with my fingers, and thinking with my brain' - me

'your story is so touching, but it sounds just like a lie'
"Straighten up and fly right"