Re: Inner tubes

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

Original poster: "Arpit Thomas" <neko4-at-dodo-dot-com.au> 

yeah, just get a block of foam and cut it with hot tools, then sand it.

*********** REPLY SEPARATOR  ***********

On 12/12/2003 at 5:19 PM Tesla list wrote:

 >Original poster: "Brian" <ka1bbg-at-webryders-dot-net>
 >
 >Hi, I think both Gary Lau and i both tried the foam in a tube.. i could get
 >it to harden but never a nice round donut. the foam just is not made to do
 >what we want. maybe if the form was hard and strong it might work. Gary had
 >one machined from foam. cul brian f.
 >----- Original Message -----
 >From: "Tesla list" <tesla-at-pupman-dot-com>
 >To: <tesla-at-pupman-dot-com>
 >Sent: Friday, December 12, 2003 2:24 PM
 >Subject: Inner tubes
 >
 >
 > > 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
 > >