[rontech]

On a good day my home built wimshurst would produce 4" of spark. A Van der Graaf generator would greatly increase the voltage.

I also made a Van der Graaf generator with a square sided perspex tower ca 3 ft high with a modified ball cock copper float as the dome. Meccano motor and mechanicals carrying a silk belt ( modern plastics for belt not available to me at that date.

Used the wimshurst as the priming source of charge. ( pointed brass pins for collectors on both machines were made from old acoustic gramophone needles )

Problem was leakage all over the place. Run in the dark, cloudy discharges all the way up the corners of the tower. Very long 18" or so feathery sparks from the equatorial seam of the copper float.

The longer sparks could be felt as a very mild tingle about 2 ft away.