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Your Terminal-
The Essential Toriod, or, Spherical Dreams

Some various methods for making a nice, shiny terminal for the monster growing in your basement

-Toroids-: a toroid is a donut-shaped metal object, the best terminal for Tesla coils. Any toroid should be at least twice the width of the secondary, better being three times.

• method3: Once again, go to your local hardware store. Here you can obtain flexible aluminum dryer duct, which is excellent for making a toroid. Also, buy yourself some aluminum tape-this will allways be handy. The duct should be wrapped around two aluminum pie pans, or anything of a similar shape, stuck bottom to bottom, so a crossection would look something like O}-{O . The diameter of the toroid will be determined majorly by the diameter of the center disk (the pie pans), but also significant is the diameter of the dryer duct itself. Secure the duct in a ring using a strip of aluminum tape.
  
  This is the terminal used for the BBC's second incarnation.

  
  These are the two toroids used in conjunction with a section of aluminum pipe for the third incarnation of the BBC.

• method1: Go to your local hardware store and buy eight 45 degree 2 inch copper pipe elbows, and enough 2 inch pipe to join them into a ring. You can also try this with four 90 degree elbows, but the discharge will all come from the corners, and less voltage will be built up. Cut the copper pipe into eight sections just long enough to join the elbows, and then solder them together the way you would normally. This will make a very fine toroid, (though expensive for the size produced) and if the center hole is larger that your coil diameter, then try using smaller pipe diameters, if your coil is very diminuative, or you can fashion a disk of metal to fit in the center hole of the toroid.

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• method2: For this you will need acess to the usual high school metals shop. This involves the melting and casting of aluminum, so this may not be for everybody. I tried it with superb results. Buy any size of styrofoam shape, in my case it was several spheres and two toroids, and carefully cut it exactly in half (this needed to be done for the type of mold my high school had). Create a mold of the shape, and cast in aluminum. When it can be removed, you will have a very rough solid aluminum object. Now you'll need to saw, file, scrape, sand, sand, sand, saaaaaaaaand, and buff the thing into a high sheen. I used a 4" styrofoam sphere and ended up with an aluminum ball almost that size, with a finish so shiny it's nasty to look at in the sun. My 2" coil loved it.

  

• method4: For this one, you may have to seek out a larger supplier than your local hardware store. DIY comes to mind, but there are many others. Purchase eight 45 degree heating or dryer duct elbows. These will connect together to form a very nice toroid, and pretty large to boot. You will need to rig some sort of metal plate to fit in the open central ring of the toroid, and this can be made from aluminu pie pans, or an aluminum bowl cam be fit in, with its bottom pointing upwards when the toroid is mounted.
• method5:Buy a big block of "florists foam", the stuff they stick flowers into to create arrangements. Force it onto a piece of PVC pipe and lock the pipe into a lathe, perferably one with a variable speed. Now use any old tool to scrape and shape the spinning peice of foam into the desired toroidal shape. Then coat this form with epoxy, using lots of resin so it will harden very well. Now, after letting the epoxy cure for a day, cover the entire suface of the toroid with aluminum tape. This can be purchased for a few bucks at a well-stocked harware supplier. It may be sold as dryer duct repair tape, "plumber's" tape, or even auto body repair tape.
• method6: Purchase a styrofoam sphere, dia. being at least twice that of your coil, and carefully cover it with either cemented strips of aluminum foil, or aluminum tape. This was done to a 4" sphere for the 2" coil, and worked pretty well. Try rubbing down the foil with an old plastic spoon, to smooth it a bit.

  

• method7: An easy way to make semi-sphereical terminal is simply use two steel mixing bowls stacked on top of eachother. These can just be secured together with electrical tape, or if you are the ambitious type, the protruding lip could be ground off, and the two halves welded together.

"Hey, my face is getting warm!", says Jesse as he presses his nose against our plasma globe

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