Mineral oil also works well. 100 gallons?!?!?!?!? What are you building with that? Good luck... Tesla List wrote: > Original Poster: "Michael J. Veach" <veachm-at-sunyit.edu> > > What kind of oil is best for very high voltage tesla-type stuff? I need > some transformer oil, but I've heard it's 300 bucks a gallon. I need 100 > gallons, so as you can guess I'm worried about price. > > Mike Veach.