Hi Hans and welcome to the Vacuum Experimenters Group.
I think you will have a lot of fun building your NIXIE tube!
You might want to check into one of your local NEON SIGN companies
to see the process first hand if you've not seen it before. If you
can get to talk to one of the technicians that makes the signs, he
can show you how to attach ready made "thru-glass" connections to
your base and also show you how to do the vacuum part. They will
have NEON and feedthroughs you can buy and torches that you can see
to get an idea of what you'll need.
A few minutes in their shop will answer a thousand questions.
Once you do that we can help walk you through the process.
Ken Hunter
--- In VacuumX@..., "Hans Summers" <Hans.Summers@t...>
wrote:
Hi
I want to build my own nixie tube. I built a nixie clock you can
see
on my webpage, see
.
Seems
fun to have a go at building my own nixie tube, as much as
possible
from commonly available items and without special or expensive
equipment. To assist in this endeavor I have a copy of G F
Weston's
1968 book "Cold Cathode Glow Discharge Tubes". At the moment I
have a
large number of questions some here might be able to help with.
Plan so far is to use an ex-English Mustard jar, measuring 5 cm in
diameter and 8cm high. This will be inverted and form the top and
sides of the homemade nixie tube. The base will be made from a
square
of ordinary glass sheet, fixed to the jar using vacuum cement. 4
holes in the corners of the square base can be used to bolt the
nixie
tube to whatever it needs to be bolted to, using plastic bolts of
course.
Cathode digits will be made from nickel wire if I can find it. The
internal supporting structure from glass or ceramic rod, again
glued
using ceramic cement. The anode mesh will be made from fine wire
wound helically around the supporting structure.
Holes drilled in the glass base will take the connecting wires,
cemented using the vacuum cement. Alternatively is it possible to
melt the glass baseplate with a blow torch and push wires through
it?
The connecting wires will be welded not soldered to the digit
cathodes. For this I plan to use a 50,000uF 100V capacitor (bank
of 5
10,000uF in parallel), based on previous experience welding a
screwdriver to the bus terminals on shorting the capacitor (and 3
ft
spark). Seems more than sufficient to weld a couple of wires
together.
Vacuum generation and subsequent neon injection will be via a
glass
tube through the base plate.
Does anyone know what degree of vacuum is required before putting
in
the neon? How about a suitable getter material to soak up
remaining
oxygen? Where can such be obtained, and is it really necessary for
an
experimental project? The tube won't have to exist in a commercial
environment with a 100,000 hour lifetime and guaranteed
specifications.
Can the vacuum be generated with a simple homemade piston type
pump?
What kind of blowtorch is required to seal the glass tube when the
gas is ready? Is a special kind of glass required for the glass
tube
and/or baseplate or is any household glass Ok?
On the subject of materials, where can neon gas be obtained (in
small
quantity)? How about a suitable vacuum cement with low outgassing
properties?
Any comments/suggestions welcome
Hans
