After tinkering with components for a year, I finally lashed together my first
Tesla coil yesterday. Inspired by a design I saw in the Lindsay Pubs. reprint
THE BOY ELECTRICIAN, I built a bipolar design, that is with a horizontal primary
and secondary, with brass terminals coming from each end of the secondary. In an
effort to keep wood and ferrous metals out of the device, I built the frame out
of 1/2 inch PVC. The secondary form is a heavy cardboard tube, well dried and
shellacked, wrapped with 11 inches of 24 ga magnet wire (250 feet of wire in
all). The primary is formed on a so-called "2 inch" PVC pipe coupling, actually
2.75 inches in diameter. It has 9 turns of insulated 12 ga. wire. I've been
trying various capacitor arrangements but the best so far is the simplest,
namely a single 4000 pF, 20KV polypropylene radio capacitor. Power is supplied
by a Allanson NST, 7.5KV, 30 mA. I have four identical caps, so I am going to
try various combinations. I have a program called TeslaMap which recommends
about 15 nF for this configuration.

I was frankly startled by how well it works. I have a smaller Tesla coil I
bought from Ken Scott, and I have seen other coils in operation, but my
"plumber's nightmare" coil is very loud and vigorous. I haven't done too many
tests yet to see how long I can draw out the streamers, but I can pivot the
terminals 360 degrees each and getting easy (and loud) six inch streamers. The
brush discharge in low light is strong, purplish and violet. Passing a clear
incandescent bulb (on an insulated handle!) between the terminals provokes
really violent plasma displays.

I will try to post pictures of it soon.

Paul Thompson