From: Chuck Curran[SMTP:ccurran-at-execpc-dot-com]
Sent: Friday, August 08, 1997 7:30 PM
To: Tesla List
Subject: Re: Toroids
> >> I have seen quite a few of Tesla Coils topped with a metal toroid.
> >> Where is everyone finding these?
> >> Are most home brew?
> >> What would an alternate "Top Cap. Hat" be? (Copper toilet float)?
> >> I have been lurking on this list and have enjoyed the info.
> >> By the way, This is my first "post" ever!
> >> Thanks...
> >Hello Jay:
> >Welcome to the list, it's proven to be an open and friendly place
> >you can normally get your questions answered very quickly. The
> >have been made in a number of different ways, but I've got a
> >If you go to your local hardware or building supply store you will be
> >able to locate the two key materials. The first is flexible aluminum
> >air ducting, which looks sort of like an accordian like material. 4"
> >diameter sections are typically available for dryer ducts. I've seen
> >also in building supply stores. At Industrial Heating shops it can be
> >purchase to 12" and over diameters. This is the stuff to make the
> >"Do-nut" part of the toroid with. One end of this ducting is tapered
> >order to plug it into the opposite end, so it fits together really
> >slick. I have used RTV silicon rubber cement to hold it together and
> >also attach it to the center flat hub. For the second material, I
> >purchased 1" sheets of foam insulation, that is clad with aluminum
> >for my center hubs. I simply cut out the round disk based on the
> >requirements, then space it up off the floor to position it at the
> >center point of the flexible aluminum duct mentioned above. I attach
> >one end along about a 6" length and let it dry over night, holding it
> >place with all those one gallon paint cans from under the work bench,
> >is it under the stairs at your house? The next night I extend the
> >around the foam circle attaching it with RTV and then I tape the
> >duct with aluminum tape. Just to make sure I got a real good
> >I've always layed sections of bare copper wire from the duct to the
> >center sheet just to make real sure there's a positive connection.
> >After it's taped (to smooth out the surface) it is really very
> >I've got one that is 6" by 40" and another 10.5" by 56" and both have
> >worked great and are still in perfect shape. The big one cost about
> >$64.00 to build, just as a reference point.
> >Hope this helps to give you a starting point.
> >Chuck Curran
> I've been trying to use rubber inner tubes from old car tyres.
> You could even use tracktor tyres for giant toroids.
> since rubber is not such a good conductor I would coat it with
> foil and then use it , I have not tried it without.
> If anyone could give comments about this...
> Kenneth Aaron
> E-mail : kennetha-at-geocities-dot-com
Several weeks ago another list member mentioned having used an inner
tube successfully, so this is probably a very reasonable approach. I do
also remember several months ago a story where the toroid was made by
coating the inner tube with foil. The inner tube lost air pressure and
the results were, ah, a collapsing disappointment. I've found that the
dryer type air duct, when coated with the aluminum tape is extremely
durable and very cost effective. It's my choice for now--try it, I
think you'll be happy with the results. A spun aluminum toroid, while
an esthetically pleasing item, is really a total waste of money for a
new coiler. Good Luck with your efforts!