The picture below shows the winder to wind the coils.
The flat capacitor is made of polyethylene foil and the covers of aluminum foil. So build capacitor was awash in oil and placed in the housing.
The film below shows the effects of this device – the discharges reach 1 meter which is quite long for that low power.
[video]http://filmy.elektroda.net/14_1306938019.flv[/video]