Re: Making a Toroid

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

Original poster: "BunnyKiller by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bigfoo39-at-telocity-dot-com>

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Parpp807-at-aol-dot-com>
>
> I am taking my first baby steps towards making my first toroids-- two 14 inch
> toroids for my bipolar coil.
> I bot some aluminum ducting from McMaster-Carr. They call it "superflex," and
> it is.
> 2 1/2 feet of this stuff will stretch out to 30 feet. No misprint. The item
> is 5525 K44
> on page 155 of the McMC catalog. I would like to know if anyone has had any
> experience with this material. The walls of the unstretched tube are 3/16
> inch thick, the ID is 4 inches,
> and the aluminum is 0.005 inches. It appears to be a tempered aluminum. It is
> spiral
> wound but the ribs are formed just by sharply crimping the aluminum. There is
> no wire support like a slinky or some dryer duct. So if you stretched the 2
> 1/2 ft tube all the way out to 30 feet, the walls would then be 0.005 inches.
> The rigidity comes from the gauge and temper of the annealing, if it is
> annealed. The unstretched 2 1/2 foot coil is perfectly
> smooth, inside and out, and looks like aluminum foil wrapping. The ribs
> are not apparent until the coil is stretched.
>
> If I don't screw this up too badly I should get some decent toroids out of
> this material,
> and I would like to hear from anyone who has used this stuff.
>
> Ralph Zekelman

Hi Ralph...

sounds like the stuff most of us use ( the same stuff from Home Depot etc.)
try to
leave the tube "compressed"... makes it more ding resistant. Once you
streach this
stuff out it becomes very weak ( remember its ducting ... made to be put
into place
and never touched again ) and it doesnt "play" well.

Definately make a center ring out of thin plywood ( 1/4" or less) to help
shape and
support the toroid.

Scot D