My TC So Far

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

Original poster: "Chris Fanjoy" <zappyman-at-hotmail-dot-com> 

   Well it's been almost a month since I started working on this project, 
to build my first-ever TC. I've accomplished quite a bit over the past few 
weeks, and certainly learned a lot in the process. Needless to say, I still 
have a lot of learning to do and I already see some potential mistakes I 
may have made. My TC won't be ready to power up for a few weeks yet, but 
here's the story so far.

   The first thing I started working on was the secondary coil. I was going 
by the bit of knowledge I had at the time, based mostly on recommendations 
from a few sites. I had originally planned to use a 2" form, but decided on 
4" instead, to accomodate more windings. Now being the cheapskate that I am 
(and living so far out in the country), I didn't want to pay big bucks for 
a piece of some exotic material. I chose PVC, since I've heard it's the 
choice of most coilers. The nearest hardware store only sold PVC in 10' 
lengths, and wanted almost $20 for a piece of 4" PVC. Not wanting to wait 
that long or spend that much money, I hunted around in the storage building 
out back and lo and behold, found a 10' length of 4" PVC. But alas, it was 
perforated (~2 holes per foot). So after cutting the piece to use for my 
form, and cleaning it up, I cut a bunch of small pieces off the remaining 
pipe and epoxied them inside my coil form. Once dry, I filled in the 
shallow! cavities on the outside of the form with plastic wood, and 
thoroughly sanded everything smooth. I pre-coated the form with 3 coats of 
Minwax Helmsman (high-temperature spar urethane - I hear polyurethane isn't 
so good). It took me a week to build the winding jig, but once completed it 
worked like a charm. It was run by an old variable-speed sewing machine 
motor, and controlled by a foot pedal from the same unit. I even added an 
electronic counter (purchased for $3.99 at an auto parts store) to 
precisely count the number of turns. The wire used was Elektrisola #27 AWG, 
and altogether I wound a total of 1,481 turns. The winding progressed 
fairly quickly (about 1 hour in all), and once completed I added four very 
thick coats of the same finish. (to avoid runs, I attached a low-RPM 
turntable motor from an old microwave oven, and left the form rotating 
until the finish was dry). Now all that remains is to glue on the end 
plugs, and continue to the rest of the components - ! I hope.....
   Doing more reading today, I see that PVC is supposed to be "dried". 
Well, this stuff was sitting in a well-covered storage shed for at least 10 
years, and in the days before the coil was wound, I left the form near the 
wood stove to allow the varnish to dry. I also wonder about the 
perforations, but I'm quite certain that these were well-sealed, and 
shouldn't be a problem.
   Now I can continue working on the other components. I'm having some 
trouble figuring out what to build for a power supply. I had planned to use 
a very large old MOT, with a diode-capacitor voltage tripler (as described 
on Greg's Garage). But I do not know how I would then determine what value 
of tank cap to use, as well as what the primary inductance should be. All 
the formulas I've seen, for determining the resonant frequency, require 
that the current output of the power supply be known. When using a DC power 
supply, how does one determine the value of these other components?
   For the sake of simplicity, I may start out with a simple OBT power 
supply and go from there.
   I can see I still have a lot of learning to do.
   Thanks for any advice.