I built this Spark-Gap Tesla Coil (with some help from a couple of friends, Jeff & Brian) from plans and parts purchased from Alan Majernick @ TeslaStuff.com. Alan ships fast, is happy to help, and has been an overall joy to work with.
And here’s a shot by day, before the final wiring and control box were completed. Photos by Melissa Bishop.
There were only a couple of hiccups getting it going, all related to arcs burrowing through the grade XX phenolic used to support the spark-gaps. I switched to nylon bolts, and its been quite a robust device ever since. Currently “in production”, the coil regularly runs 20+ minutes at-a-time.