RQ> From: pierson-at-cimcad.enet.dec-dot-com 

 dwp> This may be a DUMB IDEA.

Nope. Not dumb at all. Good idea.

 dwp> I was wandering thru the local HW store.  Noticed some
 dwp> stovepipe, including elbows.  Hmmmmmm.  Would they work?    
 dwp> The outside is not particuarly smooth, so there would be    
 dwp> corona loss, unless the leakage created a psuedo electrode  
 dwp> of ionized air... 

These work fine if the reports of other coilers are true. Best
homemade toroid I have ever used, still use, and still make:

Four inch diameter flexible polypropylene drain piping. This is
heavily ridged, and will easily bend into full circles 25 - 30
inch in diameter. I trim the ends with a knife, match the ends
together, and tape it with 3 inch wide, electrical type, friction
tape. I then cut strips of the same tape and cover the ring so
that the ridges are smoothed out somewhat. Then I cover again
with plumbers aluminum tape. Then I mount a center circle of thin
plastic inside the ring. I coat the center plate with spray
adhesive, cover the plate in foil, and smooth out and attach the
center plate to the ring with more AL plumbers tape.

These are cheap, fast, and easy to make in various sizes. They
work great. In toroid sizes larger than 12 - 14 inches, small
ridges or other surface flaws/defects do not affect the
performance significantly. 

The simple way to test the field shape and strength is to place a
protuberance of conductive material on the toriod surface until
the field shape is altered sufficiently to cause repeated
breakdowns. These breakdowns will be seen as sparks frequently
leaving the same spot. This will let you know how large a defect
will affect the toriod performance. If the sparks are breaking
out ramdomly, it is safe to assume performace standards have not
been significantly compromised.

Richard Quick
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12