First light tonight 6″ sparks, not bad for the first time I’ve powered it up.
At the moment the limiting factors to the spark length/voltage is the unfinished top load and a problem with the belt. The top load has a very uneven surface, I believe I’m losing charge this way.
When the VDG starts charging the two sides of the belt are attracted to each other and they rub together, reducing the charging. I tried tightening the belt with no effect, so I have ordered 0.4mm (was 0.25mm) latex to make another thicker belt.