4" Tesla Coil  I decided to upgrade my 3.25" PVC coil to 4" Acrylic. By salvaging the primary copper, and using scrap wood this went together with little cost.
 The plan was to make a very compact coil that I could use to play with different transformers and spark gaps.

	12 Turn primary.  .25" copper tube, spaced at .20" between turns. Inside diameter:  6.5"   Outside diameter:  19"  Supports are 3.5" high smoke plexiglas.  Normally taps at turn 11 with SRSG In the center is the receiver for the adjustable secondary.
	In the center is the 4" inside diameter PVC tube used to receive the secondary. The gear mechanism to raise and lower the secondary was removed from a laboratory oven. It allows 2" of travel.    The base is made from 3/4" plywood. All corners were rounded off with a router. Sanded then painted with gloss black, oil based enamel.
	4" OD acrylic secondary. Wire:  28 awg, formvar enamel coated Turns: 1458 Approx. 1526' wire used  Winding length:  20"       5:1 H/D ratio Inductance(calculated)   39.01 mH   After I wound the coil it was coated with about 4 layers of slightly thinned polyurethane. I wanted to be sure the wire was coated all around.  Then I applied 1 coat of "POUR ON" clear epoxy. The total amount of POUR ON used was 4 oz. for a nice thick coating.
	Check the transformer Projects page to see my current home spun transformers. Check the Control Panel page to see my current controller. Torroid: 6" X  24"

Sparks: All photos using dual 15 kV NST, 135 ma    .054uf MMC  120 BPS Rotary spark gap

Maxed out. No more space in the garage. Measured 71" from the torroid to the metal strike point.

There is a slight secondary flash over. It is the streak on the left side of the secondary. Probably need to raise the secondary a little.