🚀 go-pugleaf

jsevinsk@digi.lonestar.org (John Sevinsky) writes:

>I've been thinking about the idea of making my own neon tubes, and I have no
>idea what's involved with filling the tube with neon.  Does anybody know what
>kind of equipment is needed and how much it would cost?

You'll need a high vacuum pumping system.  Either a rotary pump and a 
diffusion pump or a turbomolecular pump.  Either costs in the thousands
new.  I saw a rotary/diffusion setup at a hamfest recently for $75
and was foolish enough not to buy it.  You'll next need a high vacuum
gauging system. Figure a grand for an ion gauge.  Sign grade neon and
argon are kinda expensive but the cylinders it comes in are even 
worse.  Figure at least $20 a month demurrage for each.  Then you'll
need the high purity regulators at about $200 each plus misc 
piping and valving.  Figure another grand for that.

That said, I'll observe that one CAN get in a lot cheaper if one is not
terribly worried about the quality or longevity of the tubes. I've
seen some pretty atrocious setups in shops I've sold gas to.  Rubber
hoses, ordinary plumbing valves and so on.  The problem is if 
large molecules are permitted in the system, they cause rapid electrode
sputtering which drastically lowers tube life.

It is a lot of fun, though.  I used to have a setup similar to what I
describe above, assembled from surplus parts.  I used it to make 
homemade lasers.  Some even worked :-)

73 John

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