"Big Slam" Tesla Coil, For CHEAP!!!!

        "Big Slam" Tesla Coil, For CHEAP!!!! or (Plastic Bottle Caps rea
        Mon, 31 Mar 1997 09:23:20 +5 EST
        "Heinz, Wahl." <hwahl-at-jtc-campus.moric-dot-org>

I’m an instructor of Electronics at the Jefferson Technical Center in
Watertown NY and  enjoy building TC’s. The most recent
one we built cost nothing. So I thought I’d post it to those who
interact with persons looking to enter the world of TC building.

Parts list:

1 furnace Xformer (10KV-at-23mA)
6 Roofing nails
20” PVC (3 ½” OD)
2 “Big Slam” Mountain Dew Bottles
1 3-gallon bucket
1 cup Rock-salt
1 quart Veggie oil
2 cups crushed ice 
4’ ¼” copper tubing
1 square foot of ¾” plywood
1 sheet of aluminum foil
400’ #22 magnet wire
24” ½” PVC 
10’ #10 stranded hook up wire


Heat about 2 gallons of water and add rock salt, dilute salt and let
Fill “Big Slam” plastic bottles no more than 2” from top.
Place bottles in plastic bucket and fill to a level ½” below level in
Add crushed ice.
Strip 1 foot of  a 3 foot piece of #10 wire and place in bucket without
letting the wire get close to bottles.
Drill holes in bottle caps.
Strip 1 foot of wire and insert through holes in caps, thus wiring
bottles in parallel.
Add ½” oil inside and outside bottles.(pour slowly or oil will mix) 
The Veggie oil is easier to get rid of than motor oil and it works as
good (or better).

Your capacitance will measure about .008 micro-farads.
Use the green Mountain Dew bottles because they have a better dielectric
strength than the clear Pepsi bottles.

Wind your coil, should come out 18” long, tight to one end.
Cut the ½” PVC into 4” pieces and notch for ¼” copper-tubing as coil
Use 4 of the roofing nails as a series spark gap.( 1/8” gap per)
Use 2 nails to protect (crowbar) the output of the Xformer.( ¾” -1” gap)

Drill hole in middle of plywood to receive PVC secondary.
Draw an 8” circle centered around secondary and evenly space ½” holes ¼”
deep to receive ½” PVC primary form.
Carefully wrap ¼” copper on primary form. 
Wad up aluminum foil for toroid.

I drew about a 6” arc off a corona point before the aluminum foil broke
down all over the place and was able to light
fluorescent bulbs at about four to six foot, once adjustment was made to
the series spark gap. I added the veggie oil to the cap
bucket after I tuned up the circuit. It reduced corona and increased
output, although it did require a little re-tuning of the circuit.
The primary was tapped 2 and ¾” turns. Wires kept as short as possible.
I splurged and bought two stainless steel salad
bowls for $.77 each (Wal-Mart) to replace the foil toroid. It required a
little re-tuning but the results were worth it. The caps
held good once the circuit was tuned up. They blow if the outer plate
wire gets to close. I started with the Pepsi bottles but
they blew to easy. My first attempts used foil on the outside of the
bottles but I had to use 4 bottles to get the same
capacitance, they blew within a few seconds of firing the circuit and
corona was almost impossible to control. Keep a supply
of bottles handy, if the water gets to warm the bottles blow. 

Happiness is a cheap Tesla….

Capt. Heinz Wahl CETma BSEET

Pictures to follow…..