Making a Toroid

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

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