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Re: Plexiglass Form

>>From SSNSanders-at-aol-dot-comFri Aug 16 13:37:13 1996
>Date: Fri, 16 Aug 1996 14:30:00 -0400
>From: SSNSanders-at-aol-dot-com
>To: Tesla-at-pupman-dot-com
>Subject: Plexiglass Form

>The form I have the merchant says is cast. I used a hole cutting bit in the
>drill press to cut a cap for the top and a 6 inch base plate for mounting.
>Both plates will have a hole in the center but no wires on the inside of the
>form. Is this an OK design or should I seal the holes completely. Also what
>would be the result of evacuation of the form and putting in neon, any
>adverse effects?     Steve

Steve,

I think it is fine to leave the holes open, especially so until 
whatever solvent/glue you use to weld the end caps on is mostly 
outgassed.  You don't want a potentially explosive solvent-air 
mixture within your secondary.  Might be a good idea to purge it by 
blowing dry air through the holes from a vacuum cleaner or better, a 
dry nitrogen gas cylinder after a few days of curing.  You could then seal them
off if you wish.

If you evacuate the interior of your plexyglass cylinder, the 
solvent/glue used to attach the ends will outgass for quite a long 
time, possibly weeks, before it settles down to the vacuum level 
being drawn.  At that point you could introduce low presssure neon 
and seal off the coil tube with an all plastic valve to the pressure 
desired.  I expect that the gas will glow brightly as in a neon sign 
and the plasma will act as a voltage shunt across the entire 
secondary reducing the total output to where a discharge streamer is 
not possible.  You will only be able to draw small sparks from a 
grounded wand brought near the top coil terminal.  After a very short 
amount of run time you will probably notice the inside walls of your 
plexyglass tube becoming coated with a milky white diffusion.  This 
would be caused by plexiglass molecules in the plastic wall being 
knocked free into the vacuum/low pressure neon space by accelerated 
neon ions acting as a random ion bombarding machine.  These 
plexyglass molecules will re-attach themselves to the inside wall of 
the tube as white dust.

I've never tried the above so I'm only making a best guess on this 
based on limited experience.  I suspect that comments on this thread 
may quickly evolve beyond the scope of Tesla 
coils and should probably be continued on the HV List, or the Noble 
Gasses in Evacuated Plastic Vessels Excited By Strong EM Fields 
list;)

Regards, rwstephens