Building a coil

Hi Andrew,

Well, since I now know you don't mind sparks longer than 1", I can make some

First, were you looking for "canned" plans or want to go from scratch.  Scratch
is really not as hard as it sounds.

If canned is what your after, you may look into one of the science supply
companies.  I built my first one this way.  I used the low power "BTC3" plans
from Information Unlimited.  See Richard Quick's posting for their address and
phone number.  But remember, with the canned plans, you are limiting yourself on
how to build it.  The plans that they sell are not necessarily the most
efficient either, but they work.  These original plans produce about 10" sparks.
I think I spent around $150 for the whole thing.  I did make some substitutions,
without problems.  If I knew then what I know now I could have done it for

There is more than one way to skin a Tesla coil.  I have since changed their
plans dramatically and tripled spark length.  I added more transformers and
changed the spark gap.

If you want the best you can get, ask more questions here and start winding a
secondary.  If you are going to use that 24 gauge magnet wire, I would get 21-22
inches of extruded acrylic 4" OD tubing (1/8 inch wall), from a plastic
supplier, and some scrap flat acrylic to cap the ends, maybe about 1/8" thick.
Cast acrylic tubing will work just fine, but is about twice the price.  I would
then wind about 18"-19" of the wire onto the tube, starting about 1/2 inch from
one end.  That's about 800-900 feet of the wire.  I hope you have that much.
Leave a couple of feet of wire for a lead at both ends.  Cap the ends with round
pieces of the flat acrylic.  Use epoxy to do this.  Use nothing with a solvent
in it.  Then seal the entire tube with many coats of clear polyurethane paint.
Use thin coats.  Thick coats will sag and run.  Have patience doing this.  It
will take days.  The windings should be completely embeded in the polyurethane.
This is not necessary for running the coil.  It is just to protect the winding.
The polyurethane also keeps the windings in place.  If you want to have a nice
ground point for the bottom of the coil, you can use a copper sheet metal plate.
Simply form it to the side of the former, solder your lower lead to it, and
epoxy it in place.  See Richard Quick's coilbld* series for details on the
ground plate.  They are available on Bill Beaty's homepage or nic.funet.fi.
This coil should resonate between 475 and 500 Khz, estimated.  It will be lower
with a toroid mounted.  Keep in mind that this isn't the only way to build a
secondary.  Its one of many.

There, that'll get you a quality primary started.

Scott Myers