I suggest that you read the entire instructable before ever attempting to build it. You may end up halfway through and realize that you don't have access to a tool or material, and waste time and money/supplies (I only had to buy the magnet wire this time!).
Step 1: Supplies
Alright, for my supplies I used:
-A 15 kV 60mA neon sign transformer (same one as before)
-16 Snapple bottle salt water capacitors/leyden jars (made more than before, check previous instructable to see how to make these).
-Lots of plywood, 1.5" diameter PVC, and some wheels for the supporting structure (Design your own structure out of whatever you have lying around, its cheaper that way)
-Spark gap from previous instructable (1/2" gap now, made from two bolts through opposite walls of 3" PVC)
-1/4" inside diameter copper tubing, 30 feet long
-Various lengths of HV and/or regular 120V, 15A wire (it works too if you keep it away from other wire to avoid arcing)
-Long metal rod to use as ground (NOT the ground for your house! Bad things will happen to the electronics you love!)
-Extension cord (to stand way back!)
-4" diameter PVC for secondary form -19" long
-800 feet of 24AWG enameled copper wire (aka magnet wire)
-A toriod (previous instructable- 3" minor diameter, 11" major)