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RE: big plasma ball

Hi all...

  Paul,
   Bill has a point about the pressure, but you didn't mention how far down
you want to pump the ball.  Just for the sake of arugment here, and my
personal curiosity...

S'pose you make a small coil...a 3" diameter x12" winding.  Make your sphere
about just large enough to cover the secondary all the way down to the
primary, but leave th. primary outside the sphere.  You'll end up  with
what, about a 20" diameter ball?  Just flood-fill it with argon (or what
have you...argon would brobably be cheapest).  You could probably affix it
to the top of a pre-existing coil.  Smaller, cheaper
definately, and won't take as long to pump down.  Problems that might
develop...
  would the arcs from the terminal break down the plexi?  does it really
have to be pumped down?  I don't imagine it would be safe to touch (whole
TC-zapping you thing), but it would look really cool :)  Now, how bright do
you s'pose it'd be?  Interesting idea!

Sundog - what separates man from animals is the use of tools and the pursuit
of frivalous hobbies....yeeeah!!!

-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, April 18, 2000 11:24 PM
To: tesla-at-pupman-dot-com
Subject: Re: big plasma ball


Original Poster: "Bill Noble" <william_b_noble-at-email.msn-dot-com>

as you figure, are you accounting for 15 pounds per square inch, or
144X15=2160 pounds per square foot of pressure as you evacuate this thing?
if you figure the surface area of your 9 ft sphere, you will see that you
have one heck of a lot of pressure to hold off - I doubt that a PVC and
plexi frame can do the trick - look up the size of plexi to use on a fish
tank (30 ft of water is about an atmoshpere) - figure the tank is 30 ft
deep.  If you go to the aquarium at Monterrey (CA) you will see that the
windows are about 4 or 5 inches thick to hold the pressure - you will need
more than an inch of plexi (I would guess) and some really strong struts and
good seals.   At least it's an interesting engineering calculation.  And,
beware of the safety issue - if it implodes, who gets hurt?
----- Original Message -----
From: "Tesla List" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, April 17, 2000 4:06 PM
Subject: big plasma ball


> Original Poster: "Paul Mathus" <pmathus-at-learningco-dot-com>
>
>      Folks,
>
>      I've been thinking about designs for a BIG plasma ball, maybe 8'-9'
in
>      diameter.  I was thinking of making a geodesic sphere from pvc or
>      steel pipe, and cauking on clear plastic sheeting, or perhaps
screwing
>      on clear plexi plates and sealing with weather stripping.  It would
be
>      a bit leaky, but I imagine you could hold gas long enough for a show.
>      You would then fill with argon or your gas of choice, pumping in more
>      as needed to replace loss while you astounded the masses.  This is a
>      possible Burning Man installation I've been tossing around for my 6"
>      coil.
[KerSnip!]