RE: Inner tubes - Failure pictures

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

Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com> 

Hi Chris:

Thanks for the details.

The polyurethane foam that I experimented with is cured by the presence
of water vapor.  I added a small spoonful of water to the inside of my
corrugated aluminum duct toroid and shook it about before filling with
foam.  I had no trouble with the foam curing to a very solid state, but
it was impossible to blindly judge when to stop adding foam with the
solid form.  An initially-deflated inner tube may provide a better
indication of filling status.

My duct toroid burst its taped-shut seam several hours after filling, so
it's probable that some improvement over a zero-pressure size is
possible.  But the degree to which this occurs and the uniformity of
expansion are questionable.

Regards, Gary Lau
MA, USA


Original poster: C T <ct451-at-yahoo-dot-com>

I made 12 1/4" cuts on the tube but my guess is that lot
more are needed. The tube, except from the part where
the label is, does look filled up without any voids. The
density of the foam inside is very low. It feels like a sponge
when you press on it.
This is a step up from my first attempt with a tube
with no vents. The foam that time was as if it was still in
the can, took forever to solidify and when I removed the can
all the air came out.
More holes could be the answer although I'm afraid the
Foam may not be strong enough to expand the tube to a
diameter of 3+ inches.

The specs for the coating I mentioned are at
http://www.cramolin.de/lackeen.htm#emilac

Thanks again,
Chris
 >  >  >Original poster: "C.T." <ct451-at-yahoo-dot-com>
  >  >  >
  >  >  >When good foam goes bad:
  >  >  >
  >  >  >http://www.geocities-dot-com/ct451/toroidart.html
  >  >  >
  >  >  >I'm thinking of using it after coating it with
  > EMV-LACK from cramolin.
  >  > Is
  >  >  >it conductive enough to work on a top load?
  >  >  >
  >  >  >Thanks
  >  >  >
  >  >  >Chris
  >  >
  >  >
  >