Making an upper Toroid terminal
- Bill Beaty, 1995

I've made a couple of small (1ft x 5in) toroids from florist's foam, that crunchy green stuff, bought from a foam supply co. in Seattle. I "cheated" by forcing a big block of foam down onto a 5" PVC pipe and sculpted it on a lathe using an old file as a scraper. I then painted it with polyester resin and coated it with that adhesive foil tape sold in hardware stores (called downspout repair tape? Metal duct tape?) I burnished the tape down with a spoon. Works great! I bet you could make a very large terminal this way by building a hot-wire bandsaw and using blocks of styrofoam. The surface needs to be painted with polyester coating or something similar, to give the foil tape something smooth and solid to stick to.

Another possible technique is to cover a large balloon with several layers of Elmer's-glue-wetted newspaper strips, then while it is still wet, carefully crush the balloon into a torus shape with some sort of wooden bracket (like a big, crude C-clamp) When dry, this papier-mache form can be coated with the same adhesive foil as above. This technique was used by a hobbyist in Wisconsin to create 4ft diameter VandeGraff terminals of various shapes.