Here are some details on my Van De Graaf generator:

It was built with a bench grinder engine with a Teflon bottom and Nylon top pulley. The ball is a garden stainless steel gazing ball and the belt is made of rubber.

3D Image

Here is the source 3D image for Sketchup 3D Van de Graaf 3D Sketchup model

Here is a small video of the generator Van de Graaf video