RE: Spheres vs Toriods

At 08:02 PM 4/8/96 +0700, Richard Hull wrote:

>Your final point about the plastic spreader is ok.  As long as the toroid 
>overhangs the winding of the coil you should be OK,  The field control only 
>relys on the donut portion.  The web or spreader does act to even the field 
>out a bit, mainly by providing a smooth even field in the center of the 
>toroidal plane.  It is not required on stacked toroids at all as this area 
>is seal off.  I still prefer the lower toroid in a stack to have a metallic 
>One fianl note.  The use of a plastic web, which is a dielectric, might 
>support and retain a nasty charge in very dry weather after the coil is off, 
>so be careful.
>Richard Hull, TCBOR

Mark, Richard:

I currently have three different toroids that I use, ranging in size from 30
inches to 62 inches in diameter.  The donut part is flexible aluminum duct.
My disks are made from styrofoam sheets (the sheathing that contractors nail
to the outside of houses under construction).  The foam sheets appear to
have aluminum foil on one side, but I take no special care to try to attach
to the aluminum foil (if that's what it is) to the duct.  These toroids work
just fine, and do provide the required electrostatic shielding for the
secondary coil.  The styrofoam sheets are 1/2 inch thick and are
surprisingly strong, and they are very cheap.  I cut them into beautiful
circles with a plain old box knife.  It's not high tech, but it works great.