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Plasma "Globe" Construction.
To construct
the actual globe was by far the most daunting task, between making
something that looked good and lasted long has been found to be
difficult to
achieve. I went through several different designs to get where I
am now. The first was flexible PVC pipe caps on a 7 in.
globe. The original globe was smashed, but I still have the
mounting hardware. (Please note, higher amperage gives more
plasma streamers, and higher voltage fills a bigger globe, a big globe
will not have as many streamers as a smaller one unless you really
boost the current or use different gases (even my tesla coil will only
make a few
streamers). Also note, lower pressures favor more streamers, but
they will be dimmer, play with gas pressure and gas choice to get the
right number of streamers, but don't just keep increasing the power:
you'll
hurt
yourself and make a system that keeps commiting suicide whenever you
turn it on for longer than 10 seconds.)
The discharge
terminal is insulated, as it is a wad of copper "scrubby pad" inside of
a glass test tube, this nicely created several streamers in original
tests, the gas in and out tubes are aquarium tubing stuck fast with RTV
silicone. The valves are IV line valves, and they sealed
well. The problems with this system was that the rubber bottom
stretched as vacuum was applied, and the aquarium tubes allowed air to
leak in, which is big time bad. The advantages were the covered
terminal created better looking (and less painful) plasma.
This is system
two, much improved but with room to get better. I used an "insulated" metal
plate on the bottom, with hand bent glass tubes terminating with nylon
tubes and IV line valves coming out of the bottom to let
air get sucked out and gas come in. It is important for me to use
glass, as with this particular design, the gas in the tube itself tends
to ionize, and this degrades the nylon if it is used alone
(also, low pressures tend to crush the tubing, and if necessary I can
replace a crushed nylon tube without ripping apart my entire globe,
which I can say from experience, is not fun (destroying intentionally
something you worked hard on
because of
the
failure of a tiny
1 cent part, ruined the whole thing, and you
did not engineer it to be
replaceable; a word to the wise, if the part costs less than 10
dollars, make it fairly easily replaceable, unless it is truly an
indestructible part!)) A small metal knob meant for a drawer puller is
situated on top of
a long threaded metal rod as my discharge terminal, the rod is
insulated with a length of painted aquarium tubing (some voltage still
leaks through, but the purple cloud around the stem actually looks kind
of neat). The globe is
sealed by means of a liquid epoxy made for finishing furniture (it is
that thick stuff in the hardware store that is supposed to equal up to
50 coats of varnish, which I must say it does quite nicely) that is set
on a rubber "gasket" on a metal plate. The globe is placed in the
still wet epoxy and drug in a scraping motion slightly tipped up to
gather
more epoxy inside of it than outside, and if necessary, epoxy is
flushed into the globe through one of the tubes until there is no
longer any leaks, although this tends to splatter epoxy on the inside
of the globe which is not good. This system worked well for a
while, several weeks actually, but eventually mechanical creep set in
in the nylon
tubes and the plasma got dimmer and dimmer day by day as air leaked in
the ever stretching nylon. I could heat seal the glass tubes but
then I could never change the globe contents if necessary (which is
majorly important, because if there is one thing I have learned, is
that a full proof system is one you can modify at a moments notice,
anything else will eventually fail). I went
to the hardware store and got some valves and mounted them on copper
tubes, but the valves leaked terrible (you can only use ball valves for
gas applications). So I have designed and started to build a new
system.
This new system uses a covered terminal (two approaches were tried and found wanting, a small light bulb with the base and insides removed, and filled with copper scrub pad was tried, but proved to difficult to attach, so the old knob terminal was coated with three coats of polyurethane, resulting in greatly improved performance, but the polyurethane faded and looks bad.) situated on top of a painted black pvc pipe (rated at 100 psi), situated in a nylon cutting board which is also the top of the enclosure (the enclosure is the mysterious box that covers every electronic commercial device, but seems to be very rare, even endangered on homemade devices). The lip of the globe fits nicely in a grove cut in the cutting board, currently it is sealed with silicone (which I swore not to use, but if my fancy discharge system doesn't work, I will need to remove the globe to replace it, which requires little effort with silicone! Luckily I got it working now and can replace the silicone, but the fumes made some interesting plasma so I'll leave it alone for a while.) I found several high pressure rated ball valves rated for gas environments (like air conditioning operations) and have affixed one of these to a copper tube coming out of the bottom (copper is bad because it draws streamers because it is a conductor, but it is way better than the nylon because it won't degrade from corona, please note, so far it hasn't leaked in several days). I have built the rest of the enclosure around the lid and viola, a complete system with enclosure! I also plan to build a professional like charging system similar to this one shown below. Checking back, it finally leaked. What happened was from the constant arcing to my copper tube wore away the epoxy there, resulting in a pinhole leak, this leak was made worse by the acetic acid fumes from the silicone, I believe the fumes may have compromised the valve itself as well, so it is back to the drawing board, I have procured some custom made glass balls on stems now, which will be filled similarly to the test tube mentioned above, and should look nice! This is important as corona may have also degraded my PVC pipe, there are many potential causes, but all would be simple to fix (except the valve, but I have some ideas there as well.) The epoxy I use will be retired, as I need one that is "low out gassing". I will also use glass as the base material, instead of sticking it fast to the cutting board directly, as this may cause gas to leak through the widely spread plastic molecules, and I am going to permanently seal the globe by melting a glass stem once everything is fixed, and all the residual air has "out gassed" from the glass surfaces (this involves heating the globe in an oven, filling it with helium or argon, and bombarding it with ridiculously high voltage, such as from my Tesla coil, detuned that is (not full power, full power could wreck the glass!). Since glass is so hard to work with I may use clay or plaster of paris, properly sealed with pottery glazing compounds (which are glass!), I need to research that avenue more before I try it though, the plaster may expand and shatter everything, which would not be good.
I am now looking for an excuse to buy the expensive gases, and actually selling these puppies (once I figure out the whole leak thing) is the best excuse I can come up with, I have seen plasma globes of this size go for 900 dollars, would you like to buy one for say $300?. Let me know, we'll talk business.
Home, Hobbies, Plasma Ball,
This new system uses a covered terminal (two approaches were tried and found wanting, a small light bulb with the base and insides removed, and filled with copper scrub pad was tried, but proved to difficult to attach, so the old knob terminal was coated with three coats of polyurethane, resulting in greatly improved performance, but the polyurethane faded and looks bad.) situated on top of a painted black pvc pipe (rated at 100 psi), situated in a nylon cutting board which is also the top of the enclosure (the enclosure is the mysterious box that covers every electronic commercial device, but seems to be very rare, even endangered on homemade devices). The lip of the globe fits nicely in a grove cut in the cutting board, currently it is sealed with silicone (which I swore not to use, but if my fancy discharge system doesn't work, I will need to remove the globe to replace it, which requires little effort with silicone! Luckily I got it working now and can replace the silicone, but the fumes made some interesting plasma so I'll leave it alone for a while.) I found several high pressure rated ball valves rated for gas environments (like air conditioning operations) and have affixed one of these to a copper tube coming out of the bottom (copper is bad because it draws streamers because it is a conductor, but it is way better than the nylon because it won't degrade from corona, please note, so far it hasn't leaked in several days). I have built the rest of the enclosure around the lid and viola, a complete system with enclosure! I also plan to build a professional like charging system similar to this one shown below. Checking back, it finally leaked. What happened was from the constant arcing to my copper tube wore away the epoxy there, resulting in a pinhole leak, this leak was made worse by the acetic acid fumes from the silicone, I believe the fumes may have compromised the valve itself as well, so it is back to the drawing board, I have procured some custom made glass balls on stems now, which will be filled similarly to the test tube mentioned above, and should look nice! This is important as corona may have also degraded my PVC pipe, there are many potential causes, but all would be simple to fix (except the valve, but I have some ideas there as well.) The epoxy I use will be retired, as I need one that is "low out gassing". I will also use glass as the base material, instead of sticking it fast to the cutting board directly, as this may cause gas to leak through the widely spread plastic molecules, and I am going to permanently seal the globe by melting a glass stem once everything is fixed, and all the residual air has "out gassed" from the glass surfaces (this involves heating the globe in an oven, filling it with helium or argon, and bombarding it with ridiculously high voltage, such as from my Tesla coil, detuned that is (not full power, full power could wreck the glass!). Since glass is so hard to work with I may use clay or plaster of paris, properly sealed with pottery glazing compounds (which are glass!), I need to research that avenue more before I try it though, the plaster may expand and shatter everything, which would not be good.
I am now looking for an excuse to buy the expensive gases, and actually selling these puppies (once I figure out the whole leak thing) is the best excuse I can come up with, I have seen plasma globes of this size go for 900 dollars, would you like to buy one for say $300?. Let me know, we'll talk business.
Home, Hobbies, Plasma Ball,
Scott Bogard. 2007