Here is my primary capcitor. I got it for an 'ok' price from Surplus Sales of Nebraska at the Dayton Hamfest. It is a General Electric Pulse Discharge Capacitor, rated at .04uF, 40kV. Also note that my homade high voltage wire was good enough to prevent any arcing from the wire to the case of the capacitor. I used polyethylene tubbing around the wire, then vinyl tubbing around the polyethylene.

T. Stewart 7-10-98