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Re: torque conv./ inner tubes
Tesla List wrote:
>
> Subscriber: scottb-at-aca.ca Tue Jan 7 22:16:14 1997
> Date: Tue, 7 Jan 1997 10:48:37 -0500
> From: scottb-at-aca.ca
> To: tesla-at-poodle.pupman-dot-com
> Subject: RE: Re: torque conv./ inner tubes
>
> I have run earth mover tractor type inner tubs, car and truck tire inner
> tubes, etc, in the early 1990s.
>
> They work great when covered with aluminum foil.
>
> I had a problem though. With the onset of winter the air in
> the tube contracted in my un-heated lab. The foil then shriveled up on
> the reduced size toroid and permenant wrinkles appeared. Refilling a bit
> actually stressed the Aluminum and it tore in a few places. Finally, I
> don't know what caused this, but I came out one day and the giant 65"
> diameter inner tube was wilted down over the Nemesis coil like a big
> silver condom! I thought this might have been the rubber succumbing to
> the UV/ozone exposure and deterioration along chemical lines took its
> toll, or just a chance punture. I haven't used inner tubes since that
> time.
>
> Richard Hull, TCBOR
>
> What about filling the inner tube with something other than air, like that
> spray insulation which quickley hardens??
Has anyone tried covering an inner tube with graphite impregnated fiberglass?
A nice even shaped inner tube should make a nice toroid. The graphite would
be conductive. Graphite impregnated fiberglass is as light as aluminum and
as strong a steel. Its the same stuff the Military Stealth Fighter is built
with. PPG in Evansville IN. sells it in roll cloth or rolls like string. The
fiberglass string would make a smoother toroid surface than the cloth but be
much harder to build than with cloth. Epoxy resin or Polester resin is used
as the binder. Doesn't cost much either if you do the work yourself.
I have also thought of taking a piece of thin wall tubing and running it
threw a tube rolling machine. A staight pipe 10' long could be rolled into a
38" diameter donut shape and the ends welded together. Most any diameter can
be rolled but the larger the diameter gets the harder it is to find someone
with a machine big enough to roll it. Its not hard to find machines that go
up to 2" dia. pipe size. Up to 6" dia. can be found if you do some serious
looking. I use to know a place in St. Paul MN. that could roll 12" but that
was 20 years ago. After a pipe is rolled into a donut shape a metal circle
can be welded to the inside. This seem like it would make a fine toroid.
What about vacuum forming a plastic toroid. There are places all over the
U.S. that do this. Make a toroid the size you want out of wood and take it
to a custom vacuum form company. They heat a plastic sheet and suck it over
the wooden pattern. Then the pattern is removed and can be used again and
again. Then the plastic form is electroplated with a metal conductive
surface. The metal surface is only a few thousands thick. Would the metal
surface get holes burned in it from the arcs when used as a toroid on a TC?
Would the plastic melt from the heat of the arcs? There is a place in town
that does this and I check with them about this. They can do 48" wide sheets
of plastic. A 48" sheet would make a toroid about 40" outside diameter and
about 8" thick depending on the plastic. Two halves are made and either
glued or sonic welded together to make a toroid. The cost is reasonable.
Just a few Ideas.
Gary Weaver