pie pan toroids

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Parpp807-at-aol-dot-com>

Hi all,
I have just completed two toroids for the ends of my 48 inch bipolar. This is 
a first
time for me so I am hoping for some input from the list.

The aluminum ducting is a 4 inch ID Super-flex from McMaster-Carr, item # 
5525K44.
Thirty dollars gets you a 2.5 ft length of the stuff that can be expanded
to 30 feet. Not a misprint.

I formed two toroids of a 16 inch OD. Cutting the aluminum with a scissors is 
easy enuff
even tho this is a very heavy foil. The problem is getting an even cut as you 
cut across
the pleating. I am going to need much more practice at that. I bot two rubber
pipe couplings for inside the toroids to join the two ends. The pipe 
couplings are a semi-
hard rubber. They are made for joining two pieces of pvc or cast iron pipe. 
They come with 
two of the stainless steel "worm-drive" clamps that you will have leftover 
for your
collection of general stuff. I bot the couplings for a 3 inch pipe. That's 
the ID, but the walls          of the couplings are at least 5/16 thick and 
the whole thing fits neatly into the 4 inch ID ducting.
Bringing the two ends of the ducting to form a neat joint is a problem. I 
drilled thru the
ducting and into the rubber insert. I tapped the holes for 6-32 MSs. I used 
nylon screws, but I doubt that is necessary. The finished joint between the 
two ends of the toroid
is very far from being neat. Actually, I don't like it. I wrapped some 
aluminum foil
around it but I am going to have to see how much corona spits out from the 
joint.   
I will know more, later.

The bipolar coil is horizontal. The 16 inch OD toroid mounts on the 1/4 - 20 
end studs of the coil. I used two aluminum pie pans as sort of hub caps to 
fit the ID of the toroids.
Sort of like the toroid is the tire and the pie pans are the wheel so the 
flare-out of 
the pie pan faces outward. I put a large piece of thin acrylic against the 
face of each
pie pan to distribute the pressure over the surface of the aluminum pan. A 
1/4-20
brass nut  squeezes the whole contraption together. As the nut tightens, the 
pie pans 
seat against the toroid and the monster goes into a true round shape.
Neat like nuthin.  :-))

It now remains to be seen how much corona is going to be spitting out of the 
joint between the two ends of the ducting. I'm afraid there is going to be a 
problem with
that.

Cheers,
Ralph Zekelman