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Re: Toroid Design
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
Mike, All,
That is a good idea, but won't work with the ordinary aerosol can spray
insulation you get at Home Depot because that stuff requires contact
with air to outgass its solvents and cure. You'd end up with a gooey
mess in your toroid that would add weight and no strengthening support,
while becoming a significant fire safety hazard from extremely volatile
vapors.
There are two part spray foams available as industrial products that
employ a hardener catalyst just like epoxy which should do the job and
I've wanted to try this myself but it remains on my enormously long
'Things To Do List'.
Please let us know if you try this.
Robert W. Stephens