Re: Toroid Design

To: tesla-at-pupman-dot-com
Subject: Re: Toroid Design
From: Ed Phillips <evp-at-pacbell-dot-net> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Wed, 23 Dec 1998 20:00:39 -0700
Approved: twf-at-verinet-dot-com

Tesla List wrote:
> 
> Original Poster: Hollmike-at-aol-dot-com
> 
> In a message dated 12/23/98 12:17:02 AM Mountain Standard Time,
> tesla-at-pupman-dot-com writes:
> 
> >  The right material is more like a thinwall
> >  (0.005"?) aluminum bellows that's fairly stiff and is shipped somewhat
> >  compressed. The 8" diameter material I purchased was about 2-2.5 feet
> >  long, but would stretch out to about 7-8 feet. It will dent if you poke
> >  it hard enough or drop the toroid, but otherwise is pretty robust.
> >
>      I was wondering if anyone using the aluminum duct has tried filling it
> with expanding foam insulation after the ends have been sealed.  I figure it
> could be injected through a small hole punched into the toroid along the
inner
> radius so it would not be seen.  So far, I have been careful(or lucky) and
> have not dented mine, but thought that this might make them a little
sturdier
> without adding too much weight to them.
> Mike

	This would take a lot of foam!!!  I have had good luck here by
reinforcing the duct with a couple of layers of masking tape, finished
off with aluminum tape.  Makes a very rigid structure, but would dent if
you dropped it on something sharp.  Same thing would happen with your
foam-filled duct.  Of course, a little more tape will make it like new
again.

Ed