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Spark disk toy
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From: Jim Fosse [SMTP:jim.fosse-at-bjt-dot-net]
Sent: Sunday, February 08, 1998 1:09 AM
To: Tesla List
Subject: Re: Spark disk toy
>----------
>From: Robert W. Stephens [SMTP:rwstephens-at-headwaters-dot-com]
>Sent: Friday, February 06, 1998 8:40 PM
>To: Tesla List
>Subject: Re: Spark disk toy
>
[snip]
>Easy as pie right?.....Unfortunately not! Forget employing plastic
>disks for any plasma display project like this you propose. In fact,
>try not to use ANY plastics in the construction of an evacuated or low
>pressure inert gas electrical discharge vessel. The plastic will outgass bigtime
>as the plasma etches it. Your pumped down and freshly charged display will
>quickly change colour and then go dead. When small amounts of plastic are
>bombarded by ions in an otherwise glass plasma globe or similar
>display, being accelerated to great velocities by the high field
>gradient electric field, the surface molecules of the plastic become vaporized and
>deposit themselves quite efficiently over the entire interior of the glass portions
>of the display. This is just as aluminum is deposited in a vacuum
>chamber onto glass to make front surfaced mirrors.
>
>If you wish to work with plasma displays successfully, I suggest you
>stick with glass panels. The other problem in a homemade device is
>that you often cannot do a vacuum bake out on the completed vessel to
>make it clean enough to last for any appreciable time.
>
[snip]
>From the Halloween-l list; check out this web page:
http://lynx.neu.edu/home/httpd/d/dlima/davelab.htm
jim
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Dave's Plasma Page
The place is a mess, watch yourself, I am going to
update soon.
[snip] {jf}
Pictures still coming soon....
Congratulations! You've found a plasma globe site on the Web. This
site is dedicated to providing information on constructing
plasma globes in your own workshop. This is not a treatise on how to
build a plasma globe for those unfamiliar with electronics,
but a reference for the serious tinkerer who wants to explore plasma
art deeper. In my opinion, some of the most beautiful art is
not on canvas or sculpted in marble; it is luminous glow of the
fourth state of matter captured within a glass globe. This area is
still under construction, so check back for
updates and new information.
Why am I doing this site?
There are some of us out here who really want to create plasma art
pieces for our living rooms or dens. We did the evacuated
pickle jar gig and were not satisfied. We know with a little more
information, a little more money, and some effort, we can
create pleasing results at home. Aside from basic magazine
experiments, we have found an absence of information, or
misleading information available on this artform. We are not here to
steal proprietary methods or capitalize on the hard work of
others. We are simply tinkerers; lovers of the combination of art and
electricity. We want to create it in our own homes.
So what is a plasma globe anyway?
You've seen them. In your local novelty shop. At museums, dance clubs,
and other places. Chances are you've touched one
and stood transfixed watching the streamers of lightning inside dance
around following your fingers. A plasma globe is simply a
display of the effects of electricity flowing through rarified inert
gases. Plasma isn't usually thought of as art which I find strange
owing to it's beauty. I'm striving to follow in the footsteps of a few
who have explored this medium of expression and who have
learned to create color and texture within a small world.
Notes about constructing your own globe:
Plasma can be created in the home workshop with reasonable expense. A
stable plasma globe that lasts for more than a few
days on your coffee table is another matter. There is a big difference
in effort and cost between the two. You must decide what
it is you want before you do anything. Do you want to experiment,
learn, become bored then move on to Tesla coils? If so your
in luck. Or do you want to make your own coffee table 26" globe with
light blue streamers to amaze your friends for years to
come? That's much harder, and this is the gap I'm trying to bridge.
What I'm saying is...anyone can stick a high voltage lead into a glass
vessel, suck it out and play with some plasma, however if
you want to make it last, or make it presentable, the chore becomes
far more involved. You then have to worry about effects
of migration, sputtering, outgassing. You have to anneal your glass,
choose your seal, etc.
The drawback to this hobby is in the equipment. When you built your
Tesla coil you could scare up the parts for a few bucks,
spend a few hours winding taping and nailing, and have a functional
unit. Plasma on the other hand requires a special habitat to
exist in. We must create this habitat first. The equipment to do this
is expensive. What's more, if you want a finished looking
globe for the den, the habitat must be constructed to last, the
hardest thing of all.
Safety FIRST
I've always included safety statements. Use common sense.
My latest observations are below. Feel free to comment.
The basic necessities for the creation of plasma in a globe are:
1. A source of electrons of high energy (ie a high voltage, high
frequency supply)
2. Atoms of gas
3. A condition of vacuum.
Click here for a short course in plasma physics
Want to learn about vacuum and vacuum techniques? Click here
Globes:
Professionals bake their globes to remove surface gases and other
impuritues. You must remember that anything in contact with
the vacuum stands to outgas and corrupt the habitat. In a professional
globe, the only thing in contact with the vacuum is glass
and maybe a teeny bit of epoxy. This is hard to duplicate in your home
lab, unless you are a glass blower.
Gases:
Noble and some others are commonly used. Including Neon, Argon,
Krypton, Helium, and others...see patent 4754199 below
for more...
As you can guess, some are easier to get than others.
2. A source of helium is your local party store. They sell disposable
canisters for filling party balloons. However the quality of
this helium may not be suitable for globes. Experimentation is
required.
3. If you don't blow your own glass, a source of globes is your local
lighting store. I have ordered 14 inch clear globes from my
local dealer. I can get an 18 incher too. Your local Home Depot will
have some globes up to about 9 inches.
4. For air alone, the globes need to be evacuated to about 1-2 torr. I
have created plasma at very little vacuum in helium. In
helium plasma can exist at lower vacuums (higher pressure)
6. Don't bother using a hand vacuum pump, make a few calls to vacuum
engineering companies in your area to find a
mechanical rotary oil.. Play the 'starving student' and you'll get one
for about $200-250. These pumps retain their value.
7. I am fortunate enough to have an Eye of the Storm to experiment
with. In my quest to recreate quality plasma, I have found
that with that globe, power supply doesn't seem to be the critical
factor in plasma quality. Why? Connecting my common
'flyback' (you know, the one with the two 3055's) supply to the Eye of
the Storm, the plasma was identical to the storm's own
supply. Waveform and frequency are important, but I believe the gas
mixture/vacuum is key element in a great globe.
8. You may notice that most professional globes have their center
terminal encased in glass. This is to prevent electrical
migration and sputtering. I have experimented with this in the lab,
hollowing out small round GE vanity bulbs and carefully
stuffing a Chore-Boy copper scrub pad inside. I coated the inside of
the bulb with a conductive silver paint beforehand. It
looked really nice but I think an uncoated bulb with the Chore-Boy
inside looks even better. Performance wasn't effected
either way. The inside of this assembly in professional globes is not
evacuated. This makes it a chore, boy, to seal everything
airtight (bulb to standoff, standoff to base with HV lead inside)
1. Safety glasses must be worn ALWAYS.
2. Implosion is a consideration, a globe used must be able to
withstand the vacuum applied. Even though my globes are thick
wall, I still keep a plexi- glass barrier between me and the
experiment.
I appreciate your comments, criticisms, knowledge.
See the Patents from the masters!
Viewing the patents can provide us with in-depth knowledge about the
design of plasma display devices. Remember, these
gentlemen worked very hard to create these devices and some even make
a living from them. Do not steal their ideas for
personal profit. In accessing the patents you agree to abide by the
following.
More patents will follow as I get time.
Robert E Myer seems to be the first plasma artist of late. His patent
is encompassing and generous in detail. It even includes a
schematic!
Patent 4379253 : Ornamental lamp and method and apparatus for
operation thereof (actual pages)
Larry Albright's patents follow:
Patent 4956579 : Plasma Display using a double-walled enclosure
(abstract only)
Patent D326574 : Displayer for charged electrical particles (actual
pages)
Patent 5281898 Display Device (actual pages)
Bill Parker's patents follow:
Patent 4963792 : Self contained gas discharge device (abstract only)
Patent 4754199 : Self contained gas discharge display device (actual
pages)
Patent D322489 : Decorative gas plasma light display (actual pages)
Wayne Strattman:
Patent 5383295 Luminous Display Device (actual pages)
Others:
D302867 : Decorative plasma arc display (Warren E Dennis, Venture
Research, CA)(actual pages)
Plasma Artists and Manufacturers on the Web
Here is a nice site someone sent to me. They make very interesting
looking scultures. Check out the cool Java title screen too!-
Digitropolis
There are a select few that make plasma their career. Check out these
sites.
One person who has a deep understanding of plasma as an art form is
MIT graduate Bill Parker. His sculptures can be seen at
the MIT Museum in Cambridge Mass., as well as the Museum of Science in
Boston. Bill has several works on display at the
San Francisco Exploratorium Click (here and here) as well as his own
company page at http://rhombus-dot-net/orb/
Another plasma artist is Larry Albright. It was he who worked with
Rabbit Systems to market the Eye of the Storm. See his
interview at www.armchair-dot-com/warp/albrite.html Larry has his own
company page also at http://www.plasma-art-dot-com/
Strattman Design does creative plasma for large scale displays and
motion pictures. His Luminglas (tm) was seen in the Star
Trek movie "First Contact" as well as in Voyager.
Another plasma artist is Mundy Hepburn. He seems to have no web page,
but I did find this page on him once, and then there
was no more.
Know anyone else?
Contstruction articles on plasma globes in books and magazines (more
to follow):
Radio Electronics, March 1988, "A Universal Power Supply For Plasma
Display Devices"
Gadgeteers' Goldmine by Gordon McComb, TAB Books (Division of
McGraw-Hill) 1990
Links
Society for Amateur Scientists
Andy Clarkson's 555 timer utility (really cool)
Thank you for visiting my page. If you have comments, corrections, or
would like to add your knowledge or experience please
write.
Dave dlima-at-analogic-dot-com