Yup, 2% Ar will work just fine. Striking voltage may be a little higher,
maintaining voltage should be about the same.
That's OK I guess, since I am not trying to optimize the mixture, I am just
trying to get started. I have a 500V power supply @ 50mA available, that should
work.
Yeah, that should be plenty. Start with a largish anode resistor and reduce it
until the entire cathode is lighted (but avoid
getting over a few milliamps flowing).
What is the difference between a tack and a spot welder? I was going to look
for a spot welder (although you can actually build them yourself).
A tack welder uses a capacitor discharge for a quick weld. A spot welder uses
high current to weld. You can build
both of them yourself, and either should work fine for tube/nixie building.
The usual approach to an easy spot welder
is to remove the high voltage secondary from a microwave oven transformer and
replace it with a few turns of heavy
(8 gauge or so) wire.
For cathodes (and the anode mesh) I am planning to use 1.2mm stainless steel
wire.
Worth a try. I'd probably try nickel or iron, but almost anything should work
to start with.
But what should I use as a glas frit?
Schott makes some solder glass that should be suitable:
http://www.schott.com/
Alternatively, if you can get some large bore (20mm - 30mm diameter) lead glass
tubing, you should be able to seal
it directly to the stems using a crossfire or even a hand torch and some care.
You'll probably want to anneal it before
pumpdown.
And what kind of burner for melting the glass is appropiate? Propane and oxygen?
The sort of tools used for neon glass work should be suitable:
http://www.egl-lighting.com/cannonfires.html
http://www.egl-lighting.com/torches.html
A glass lathe would be ideal, but might be a bit expensive to start with. Or
you could try building your own (the concept
is simple, two chucks that rotate in synchrony).
Propane and air is probably sufficient, but oxygenating it can get you some
extra heat. Some neon benders use the
sort of oxygen concentrator used for medical purposes to enrich the air stream
without needing bottled oxygen.
Thanks! But at the moment I will go for wire cathodes "National Union style" ;-)
Makes sense. May I assume that the stems showed up?
- Cheers,
John
