I used to spot weld wires for electrodes by placing them across and weld. That works but doesn’t look well and I think it makes strain in the glass when sealed (more steel wire in glass, different thermal expansions). I decided to make a simple jig from some aluminum junk so that I will be able to produce nice lead-in-wires for my experiments.
The most difficult part of the tube will be definitely stems. More than 10 pins must go through, all vacuum tight of course, on small area. I have some ideas about how to do it properly, but the set up will be pretty complex. Furnace with inert atmosphere, high temperature (around 1000ºC), some kind of pressure (maybe just some ballast weight on the top of the mold..).
I spent last two weeks by making completely standalone argon tubes. I wanted to learn how to make a vacuum-tight feedthroughs and try to tip off the tube from filling system. I prepared a simple manifold for filling with argon, what turned out to be leaky, but I didn’t go for super purity gas and it was tight enough to tip off the tube. I am still waitingfor some glass components to make better manifold.. This experiment should also give some view of cathodic sputtering effect.