I've just finished another of my long term parts-collection projects - my first Van de Graaff generator:
The mechanism is built around a glass guitar slide for the bottom roller, a bit of 25mm PVC conduit sleeved with some silicone rubber tube at the top, and neoprene strip for the belt.
Plus various 3D printed parts & mechanical bits.
The dome is made up from some kind of jelly mould I saw by chance on ebay, plus a stainless steel bowl; it works, though there is some arcing and occasional streamers from the joint, as the mould has a small rolled edge. The kapton tape wrap over the joint made a massive difference and the arcs increased from under an inch to near a foot at times - though still some strays and leakage under the tape.
The acrylic tube is 1m tall and 90mm o/d.
These images are stills screengrabbed from video, so the quality is not brilliant, but they show the results!
Looks good! I need to get busy and finish making mine, bought the stuff years ago and it just is sitting in a box in the attic. I really like static electric spark making stuff.
Long ago, when I was back at school, the Physics teacher set up the Van De Graff generator on the edge of a bench, placed a wooden stool on the floor nearby, and stood a long haired pupil on the stool, with their hand placed on top of the dome.
He then switch the generator ON, and (as you would expect) the pupils hair stuck out in a nice large 'ball'.
The teacher then explained what was happening, and why - all the time walking round and gesturing with his arms.
Unfortunately he got too close to the pupil, and a huge spark leapt from the pupils nose to the teachers fingers