[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Large Plsma Tube



Hi Scott, All,

Wayne Strattman of Strattman Design (http://www.strattman.com/) is a master of large plasma tubes and globes. I had the privilege of visiting his shop in Boston a couple of years ago and he had an amazing range of very nice equipment and beautifully made stock, from simple neon stuff to amazingly intricate sculptures.

Wayne told me a story about one of the workers at his glass supplier who was permanently scarred in a fairly horrific way by the implosion of a large sphere whilst vacuum testing. From Wayn's description of the accident this guy was lucky to escape with his life.

The guys who work for Wayne have been doing this for years, and they still have the occasional nasty accident. I'm not saying you shouldn't try this at home folks; I'm sure someone on this list has a vacuum processing system that would put Wayne's to shame. But before anyone orders their 36" sphere, they should bear in mind that handling large fragile pressure vessels needs a heck of a lot more thought that just 'apply vacuum, add gas and seal'.

Safe Coiling,

Nick
--
_____________________________
HVFX Ltd. - Managing Director
Mob - + 44 (0)798 514 1873
Tel - + 44 (0)207 060 4839
Fax - + 44 (0)207 117 3065
www.hvfx.co.uk

Scott Bogard wrote:
I order 12-in lighting globes from renovators supply warehouse for $9, http://www.rensup.com/globes/40004.htm
but depending on your patience level, it may not be worth the effort to build a sealing/discharge system.  I have been told you can order complete globes up to 36-in from corning glass, but you will pay a little more than $9!  And I can't find them on their website.  But if you did get one, all you would need to do is apply vacuum, add gas and seal.  Good luck, I'm sure others will provide useful insights as well.

Scott Bogard.

Date: Sun, 2 Dec 2007 11:36:48 -0800
From: btmeehan@xxxxxxxxx
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] Large Plsma Tube
CC:
Where do you guys get the big globes from?  (or even medium or small sized
globes)  Do you have to have a glass-blowing setup in order to really play
with these things or do you just order pyrex chemistry glassware?

On Dec 1, 2007 7:35 AM, Bill Lemieux <gomezaddams@xxxxxxxxx> wrote:

PS: I forgot to mention the end-seals.  Because the ends will probably
have to be flat, you should consider using 1/2" thick plate to span a
6" distance.  This is a bit on the overkill side for 15PSI of
pressure, but better safe than sorry!  Make sure you don't introduce
any small cracks when you drill the plates for your electrodes, and
polish all edges to eliminate sharp edges or pits from drilling or
cutting.  Use fine emery paper for this.

Forget about using plastics for your end plates, it won't last.  Among
other things, atmospheric helium and hydrogen will leak in (through
the material) over the passing years... possibly changing the
appearance of your discharge significantly. You're going to have
problems with that using epoxy seals anyway, but if the exposed area
of the epoxy seal is tiny and the thickness great (ie; .25") they
ought to be good for many years.
The higher pressure you can operate at, (approaching atmospheric) the
slower this leak problem will be.

This is why old epoxy-sealed HeNe lasers died after about ten years -
the helium would diffuse out through the seals.  Amazingly, because
there was still a low pressure inside the tube, you could rejuvenate
those old tubes by sticking them in a bag of cheap balloon helium, and
operating the tube - you'd check it every few days and eventually it
would be working as good as new.  Take it out of the bag, and it would
once again be good for years.  Of course, with modern diode lasers and
even cheap hard-seall HeN lasers being so plentiful, that isn't worth
the effort.  Epoxy-sealed HeNe lasers are worthless now.

 - "Gomez"
 _______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_________________________________________________________________
Your smile counts. The more smiles you share, the more we donate.  Join in.
www.windowslive.com/smile?ocid=TXT_TAGLM_Wave2_oprsmilewlhmtagline_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla