My coil. And still learning!

["Al Hassick" <uncadoc-at-juno-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Well now!  i would like to offer what I have learned about the Tesla's.
And believe you me, there is much to learn, and I am still learning!  For
starters I  wound my first Tesla on a 3" piece of cpvc pipe with #23ga. x
28" high with  Roebling scc wire, I happened upon an old spool of this
wire. Yep, just like Tesla used to use, I wound about a thousand turns. 
I got a measly 2" spark from this first coil, but I was delighted to get
any spark at all!  I at first used a 20ma. oil burner tranny and a six
pack of salt water beer bottle caps.  I then went on to find two more OBT
at the local wrecking yard and they were all good!  So I placed them into
the Tesla and it did not work any better, even though I phased all three
of my OBT's .  So I wound a second coil on two big oat boxes which were
spliced together,  The new oat box coil with its five inch diameter  x
20" high secondary gave me a much bigger spark from my  newfound Tesla,
but I was not satisfied with the 5" spark that I had.  So I purchased a
8" cardboard concrete form from the local builders supply store and then
I went to the nearby "Penn coil co." and purchased a 7and 1/2 pound roll
of scrap 18ga. motor wire from them for a modest fee.  I then gave my 8"
cardboard concrete form seven coats of Minwax poly satin polyurethane
inside and out.  I then poured tiger hair fiberglass compound into the
interior of the 8" form and capped both ends tight with a particle board
disc on top and bottom of the secondary coil.  I also placed into the
center of the end caps a 1/4-20 bolt which I sealed very well with
automotive fiberglass resin. And then sealed the remainder of the
interior of the tube with fiberglass resin by tilting the secondary tube
back and forth slowly until I guessed all of the interior was covered. 
The 1/4-20 bolts protruded past the particle board end caps by about 1"
or so, so that I could attach a top load via the 1/4" protruding bolt. I
then purchased two 60ma. 15kv neon from Howie of Just Neon.  Howie is a
really nice, down to earth guy.  I then coupled the two new 60ma neons to
my new 8" x 25" coil wound with the 18ga. wire and  it blew me away!!!! 
I got a massive purplish corona and 30" sparks as I fine tuned my 3/8"
primary coil. (which had 14 turns) I tuned it at about eight turns.  I
ran short on the original primary tubing and I had to couple two
different lengths of 3/8" tubing by a swage joint.  Which I brazed with a
silver solder.  It turned out real good and exceptionally sound
electrically.  I would recommend refrigeration swage joints to all of
you!  They are tight and well coupled.  But Then, Just as I was enjoying
my new found sparks, the whole Tesla went dead!  I had shorted out both
of the neons.  I then proceeded to disassemble the neons and spent the
better part of two days chipping tar from the Allanson neon x formers.  I
chipped them as they stood, I did not heat them up.  I found the carbon
tracking paths and scrubbed as much carbon and tar from the secondary
windings as I could. The tar chipped away easily and then I immersed the
chipped coils in kerosene.  The kerosene dissolved all the clinging tar. 
I then took out two shunt leaves from each side of the transformers for
an improved power rating  and reassembled them and gave them three thick
coats of Minwax semi-gloss polyurethane.  When I hooked up the  newly
rebuilt neons to the 8"x25" secondary I was astonished!  The top of the
secondary was emanating 3 to 4 foot sparks!  I then built a safety gap
for the neons and then I built a switchable resistive load out of four
4500 watt water tank heater elements.  I set them up as switchable by
ordinary SPST house light switches in a ordinary gang of common steel
junction boxes.  By switching in and out the various heating elements I
was able to achieve better than five foot continuous sparks from my 8"
secondary coil, which by the way, I had also treated with the fiberglass
compound on it's interior.  My caps were all double ganged barium
titanate doorknobs of 4700pf at 40kv.  I have 30 0f them double ganged
for a final set of fifteen on a set of aluminum rails, which I purchased
from the home improvement store.  When I shunted out all the line
switches I was able to get a prolonged set of 5 foot white hot arcs
continuously from my small toriod ball.  (it is an 8" childs rubber
hollow ball that  I covered with aluminum 2" wide  commonly available
insulation tape). I can only say that many builders are espousing the
MMC's but I for one prefer the good old barium titanate doorknob caps. 
They last forever if stacked properly.  They may cost more at first, but
I think that they have got the MMC's beat hands down.  My opinion is that
the mmc's are ok for limited runs.  But If you really want to test your
Tesla, the barium titanate doorknobs will last and last. And yes, I did
assemble multiple stacks of mmc's with their  limiting resistors and I
can only say that, the barium titanates, although more costly at first. 
Are a heckofa good cap for long duration runs. I am talking of Teslacoil
runs of an excess of 30 minutes!  I have ran my 8" coil for over an hour
with the barium titanate caps, and the caps in the array I had did not
even heat up measurably.  I did destroy mmc cap gangs with a prolonged
run.  I realize that this is extra long and that this is my first post,
but I had to get in my opinion.  Hope I did not bore all of you with my
prattle.  But my idea is, that you can develop a working Tesla system for
next to nothing if you hit the scrap yard.    UNCA AL.

 

On Fri, 01 Sep 2000 11:55:09 -0600 Terry Fritz <twftesla-at-uswest-dot-net>
writes:
> Hi Al,
> 
> 	You test message reach me.  From this point on "nothing can 
> go wrong" :-))
>  I won't post this test to save bandwidth but your messages seem to 
> be
> coming through fine.
> 
> Cheers,
> 
> 	Terry
> 
> 
> 
> At 10:46 PM 9/1/00 -0400, you wrote:
> >Just testing to see if I can really reply to the list!  Unca Al.
> >
> >On Thu, 31 Aug 2000 17:40:35 -0600 "Tesla list" <tesla-at-pupman-dot-com>
> >writes:
> >> Original poster: "Jim Lux" <jimlux-at-jpl.nasa.gov> 
> >> 
> >> Since coupling isn't really an issue (where the physically 
> smallest 
> >> primary
> >> would be useful) in telsa coils (too much coupling is usually the 
> 
> >> problem),
> >> I think uniformly spaced primaries are probably easier to work 
> with;
> >> designed with enough margin...
> >> 
> >> However, since you mention it, it would be kind of cool looking, 
> and
> >> elegant, to have a variable pitch primary.....
> >> 
> >> ----------
> >> > From: Tesla list <tesla-at-pupman-dot-com>
> >> > To: tesla-at-pupman-dot-com
> >> > Subject: Re: calculating safe primary turn-to-turn distance
> >> > Date: Wednesday, August 30, 2000 9:35 PM
> >> > 
> >> > Original poster: "Jon Rosenstiel" <jonr-at-pacbell-dot-net> 
> >> > 
> >> > 
> >> > ----- Original Message -----
> >> > Subject: Re: calculating safe primary turn-to-turn distance
> >> > 
> >> > Malcolm, all,
> >> > 
> >> > Would there be any advantage to building a pancake primary with 
> 
> >> the below
> >> in
> >> > mind? Inner turns closely spaced where the voltage gradient is 
> >> small and
> >> > progressively wider spacing as the turn to turn voltage 
> gradient
> >> increases?
> >> > 
> >> > Regards,
> >> > Jon Rosenstiel
> >> > 
> >> > <snip>
> >> > 
> >> > > Well the inner turns exhibit less inductance per turn so
> >> > > perhaps the gradient ought to track the length of winding per
> >> > > turn e.g. for the outer turn to the its nearest neighbour, 
> the
> >> > > gradient will be highest as will the length of conductor and
> >> > > so on inwards.
> >> > >
> >> > > Regards,
> >> > > malcolm
> >> > >
> >> > >
> >> > >
> >> > 
> >> > 
> >> > 
> >> 
> >> 
> >> 
> >
>