I have been trying to build a small Van de Graaff generator based on the designs found here: http://rimstar.org/equip/build_make_van_de_graaff.htm Unfortunately I haven't been having much luck. How can I improve it? https://scontent.fsnc1-1.fna.fbcdn.net/t31.0-8/13692923_587926388052702_8808151424123490542_o.jpg The body was 3D printed using PLA plastic. It encloses the rubber band belt completely. https://scontent.fsnc1-1.fna.fbcdn.net/t31.0-8/13735540_587926381386036_2540663988244643720_o.jpg The bottom motorized roller is made PCV electrical tape and a slice of PVC tubing: https://scontent.fsnc1-1.fna.fbcdn.net/t31.0-8/13698065_587926361386038_7472904692042366737_o.jpg The top roller is made of nylon thread: https://scontent.fsnc1-1.fna.fbcdn.net/t31.0-8/13680297_587926378052703_6114147970296557842_o.jpg The rubber band is one of those used to hold together vegetables from the supermarket. The configuration is shows below. https://scontent.fsnc1-1.fna.fbcdn.net/t31.0-8/13723871_587926374719370_906130344536881567_o.jpg I have used many combinations of many materials for each part. I have tried using steel drinking cups and silver cups for the metal domes. I have tired thick, and thin rubber bands fro the belt, as well as balloon rubber for the belt. I also tried multiple materials for the motorized roller, including only teflon tape, only PCV electrical tape, and the current design with the PCV piping. The generator does work, as I have measured potential differences between the two cups using a multimeter, but it doesn't create arcs. Do I need to insulate the metal better?