TESLA COIL HINTS
W. Beaty 1996
On winding secondary coils: PVC pipe is probably the best thing you
can use. This gets expensive on extremely large (10 ft, 12in dia.) coils,
and baked/varnished cardboard "sonotube" concrete forms are usually used
then. If you ever use cardboard, its a good idea to lower its
conductivity by painting it with many coats of varnish, or that
The first coil I tried (back in 1981) I did on very heavy cardboard tube
diameter, and put several strips of clear doublestick tape along it to
keep it from sproinging off while winding when I let loose of the wire.
This worked fine. Wax might work, but it would have to be sticky.
I cobbled together a winder by taping 8mm movie reels to each end,
mounting one end in my old plastic 8mm movie editor, and sticking a rod in
the other end , with the rod stuck through a cardboard box support. It
worked fine, handcraking the editor and handfeeding the wire. My second
coil (in 1993) I did on 5" pvc pipe with double sided tape strips on the
used a lathe with a footpedal speed control, and hand-fed the wire using
leather gloves. On both coils I painted them with polyester resin, the
kind used for fiberglas coating. You have to use lots of catalyst in the
resin when doing thin coats, or it won't harden.
Since hand-winding a coil without mechanical aids takes hours and hours,
I strongly suggest spending a few hours to figure out some sort of winder
scheme. Winding on a lathe took me only about 20 minutes, and most of that
time was because I kept letting the turns overlap, so I'd have to stop
and unwind slowly to correct the kinked turn.
One thing I had trouble with was sparks jumping between the primary
and the main coil. The higher the power supply voltage, the better, but
at some point the voltage creates unwanted arcs. The solution is to wind
the heavy primary turns on an excessively long tube, so the spark path has
to go a long distance to get to the main coil.