Re: Inner tubes

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: robert & june heidlebaugh <rheidlebaugh-at-desertgate-dot-com> 

I have not tried to make a toroid, but As a suggest ion Try working on the
outside. Fiber glass resin mixed with some small amount of fiber such as
wood flour from a cabnet shop  sanding area (free) or chopped rock wool
insulation will make a thin paste to coat your air filled tube. Spray "Pam"
or other fry pan spray on the tube as a mold release and coat the top half
of the tube. after it hardens some turn it over then coat the other half. If
you make fhe paste to thick you can use it as a mold. After compleat coat
your toroid with a  conductive paint like spray galzanize coating. Then you
can even plate it if you like. I have used spray foam with the same poor
results you have had. While I havent made toroide this way I have made
aircraft parts and gold pans this way with good results. I use the outside
casting as a mold ( 1/2" thick) and use conventional fiberglass as a copy.

          Robert   H
-- 


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Fri, 12 Dec 2003 12:24:05 -0700
 > To: tesla-at-pupman-dot-com
 > Subject: Inner tubes
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Fri, 12 Dec 2003 12:29:31 -0700
 >
 > Original poster: "Chris" <ct451-at-yahoo-dot-com>
 >
 > I've been trying to fill a 400x8 inner tube, the perfect size for my mini
 > coil, with construction foam without any success for a wile now and I was
 > wondering if anyone experimented with this idea.
 > The first time i tried just spraying some foam inside the tube and letting
 > it dry. This didn't work. The foam did solidify but when I removed the can
 > air trapped inside came out and the tube shrank.
 > Then i decided to puncture a bunch of holes all around another tube and
 > then fill it with the foam. This failed as well but got some pretty
 > sculptures from where the foam came out of the holes. Again the tube shrank
 > non-uniformly even though a lot of foam came out.
 > The foam does not set uniformly under pressure and the gasses separate and
 > escape.
 > For my next attempt I'm thinking of either keep shaking the tube so that
 > the gas is mixed with the foam until it solidifies or put the tube in an
 > airtight box and suck the air on the outside so that there's less pressure
 > inside the tube when the foam expands.
 > But perhaps there's a better approach or a different material I can fill
 > the tubes with.
 > The coil works fine for more than 45 mins on a run with an aluminium tray
 > as the top load but it would look so much better with a toroid.
 > These tubes cost about $1.50 each and the foam about  $4 for each attempt
 > so any help welcome,
 >
 > Chris
 > _____________________________
 > CYTANET WebMail
 > http://webmail.cytanet-dot-com.cy
 >
 >