Tesla coil

In 2008 I was in high school, 3rd grade. I made an agreement with my teacher to make a Tesla Coil as my final work of high school. In Croatia, if you go to technical high school, you had to make some work, write a short paper about it and present and defend it in the 4th grade, as a graduation.

I knew what I was getting into, but I wanted to make it, and it being my final work meant my parents wouldn't argue as much.
I began to collect the materials. I used a PVC drain pipe to hold a wire for a secondary. Toroids and metal spheres were out of my budget so I used a glass bowl of the lamp and covered it in aluminium foil to serve as a top load.
I had to buy a 120W Neon transformer as a power supply, and thin insulated wire for secondary.
At first i used an electric drill to rotate the rotary spark gap. Later, before the graduation I converted the spark gap to use a small washing machine water pump motor.

To reduce cost, I used empty beer bottles as a capacitors (Layden jar). Outer side of the bottle was wrapped in aluminium foil to serve as one capacitor plate. The foil was wrapped with electrical tape so that it's insulated. The bottles had a straight wire that went throught the cap and inside the bottle, inside a saline solution, with a bit od vegetable oil on top of the saline solution to act as an insulator. After a year, I had to replace the saline solution because it didn't work, my guess is that salt from the solution crystallized and dropped out, making the solution less conductive.

This worked, against all odds. At first I had some trouble with the grounding. We stuck a big rod in the ground and wet it with water and then it worked much better. We had a big neon tube and it got light up, and we also got around 15cm long streamers from it.

Second version of the Tesla coil was much smaller, used similar high voltage power supply as the first tesla coil, used factory made capacitors and static spark gap. But I couldn't get streamers longer then 5cm from it. Tuning it didn't seem to make much difference. I fiddled with it for a while but decided to put it aside for time being.