Re: toroid parts...

At 04:25 AM 8/14/96 +0000, you wrote:
>> Subject: toroid parts...
>From sgreiner-at-mail.wwnet-dot-comTue Aug 13 19:45:41 1996
>Date: Tue, 13 Aug 1996 19:37:55 -0700
>From: Skip Greiner <sgreiner-at-mail.wwnet-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: toroid parts...
>Tesla List wrote:
>> >From ntesla1-at-vm.sc.eduSat Aug 10 13:35:39 1996
>> Date: Sat, 10 Aug 1996 13:46:10 -0300
>> From: Dan <ntesla1-at-vm.sc.edu>
>> To: tesla-at-poodle.pupman-dot-com
>> Subject: toroid parts...
>> Hi all,
>> Recently I was in the Newark, New Jersey airport (USA), and I saw a really
>> amazing thing: (don't laugh now ;)
>> All of the trash cans in the entire terminal are topped with really nice,
>> spun aluminum toroids. All anyone would have to do is cut the toroid off the
>> top of the can, attach a center-disk, and that would be it, no problem.
>> There seemed to be two sizes: (esimating from memory) 5 or 6 inches by 24
>> inches, and 8 inches by 36 inches. And being mass-produced trash cans, they
>> can't cost *too* much, but I had little inclination to try and find out
>> where they buy their trash cans during a half-hour lay-over. ;) I only
>> mention it because someone might find the company that makes them, and if
>> they're already set up for that type of spinning...
>> Also, I was at our local Home Depot do-it-yourself store, (Columbia, South
>> Carolina) and noticed that they had aluminum ducting, like the type one
>> would use for a clothes-dryer exhaust conduit, from 4 inches in diameter, in
>> 2 inch increments, up to 10 inches in diameter! And none of the conduit was
>> expensive. However, the material is easily dentable and requires care in
>> handling. I figured if I was going to buy say, 3 of each size amd make
>> toroids of varying diameters, I might go ahead and fill each one with
>> polyurethane packing foam, the kind that sprays from a can and expands to
>> fill the packing space. (After the toriod is completed of course) The foam
>> wouldn't provide *that* much more support, but some is better than none.
>> Thoughts?
>> Dan  <ntesla1-at-vm.sc.edu>
>I think you will find that whatever you use to reinforce the center of
>the toroid will make the entire assembly very stiff. I have used
>masonite and just plain 1/8" plywood with excellent results. I use a
>bead of alumunum glue on both sides of the center piece to firmly attach
>it to the duct and let it dry well. Then I connect the center mounting
>hole to the toroid using aluminum tape with adhesive on one side.
>Good luck
Hi All -

Has anyone tried to test these duct toroids for capacitance to compare them
with spun aluminum toroids? They appear to have very low capacitance.

John C.