Re: Toroid construction hints

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

Original poster: "June Heidlebaugh" <rheidlebaugh-at-desertgate-dot-com> 

Ian:  I also use stiff ducting  with out stretching it for toroids.To join
it I use mechanical joints with a spot or  two of epoxi to bond the joint. I
first neatly flatten about 1" of one end with a hammer over a pipe making a
neat line of flat area. Then I crimp the flattened area like a stove pipe
joint and slip that end inside the un flattened end and bond the joint. No
tape used. Then I use "Pie pans" to make the center with a brass lamp bolt
( a 1/8 pipe all thread) to hold it all in place.  A 1/4 brass toilet bolt
just fits inside the lamp bolt and makes it removable. No tape, No
capacitive joint , No arc point.
    Robert   H

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, February 13, 2004 8:06 AM
Subject: Toroid construction hints


 > Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au>
 >
 > Hello coilers,
 >
 > I have a question regarding the use of aluminium corrugated ducting for
 > toroids.
 >
 > I have two toroids on my system.  Bottom one is 2.5"x17" with a SS plate
 > (pizza plate) in the centre.  This joins via a 0.25" central hole to the
PVC
 > bolt on the top of my secondary, and sits about 1 inch above the top
 > winding.  Top toroid is 6"x28", with no centre plate, it just sits on top
of
 > the bottom toroid.  Looks great.
 >
 > When run, the streamers come out nice and horizontal from the top toroid.
 > No breakout from the secondary winding is noticed, no racing sparks, and
no
 > visible corona anywhere to speak of.  I have however noticed a small
problem
 > ...
 >
 > My bottom toroid is foam noodle, carefully joined with epoxy, and very
 > carefully covered in aluminium foil strips, each glued down with sparing
 > amounts of PVA glue.  The SS plate has a 0.5" lip, so I cut a 0.5" slit
 > around the inner diameter of the foam noodle and the lip slots into this
 > slit the entire way around and is held firm.  It came out really smooth
and
 > nice and (although I was worried about it with the glue) conducts around
the
 > entire toroid from the central plate.
 >
 > My top toroid however is 6" stiff aluminium corrugated ducting, held at
the
 > join with aluminium tape ("FlashTac"), that stuff with the thick layer of
 > bitumen on the back.  That is all I could find in aluminium tape.  I
cannot
 > get it to conduct to the toroid because of that thick bitumen adhesive,
and
 > the coil favours this spot on the toroid for break out.  Why would it pick
 > this spot, when it is not conducting to the toroid?  Is it because it is
 > capacitively coupled to the toroid?, or is it just simply because it
 > provides a rough spot for breakout?  I thought I had smoothed the tape out
 > pretty well, but it is certainly not as uniform as the ducting itself.
Any
 > ideas anyone how I can improve this situation ?
 >
 > Ian
 > Ian.
 >
 >