Steps 9 and 10

Step 9: Wind the Primary

If you haven’t already, finish varnishing your secondary before you proceed.

The primary coil is 6 turns of wire that’s wound on top of the secondary turns, slightly above the bottom of the secondary coil. We strongly recommend putting an additional layer of electrical tape or kapton tape underneath the primary, on top of the secondary’s varnish, to add to the resiliency of your coil.

  • A. Tape down the end of the primary to hold it in place. Wind 6 turns without overlapping the wire.
  • B. Twist together the ends of the wire to hold the coil in place.
  • C. Tighten the twist with a pair of pliers to remove any slack in the windings.


If you coil the wire sufficiently tightly it will stay in place by itself. If you want it to be slip-proof, use a small amount of hot glue or tape to hold it in place. Just remember that if you need to add more varnish to your coil later, you will need to remove the primary!

Wind the primary   Twist the wires


Step 10: Attach the Primary Connector

  • A. Cut the red and yellow wires of your primary connector so that they are about half an inch long. Using wire strippers, remove about a quarter inch of insulation from the end. Leave the middle wire long.
  • B. Cut about half an inch off the end of the primary wire to shorten it, and strip about a quarter inch of insulation. When you are finished with mounting the primary connector, it should reach just into the notch in the secondary tube to the connector on the main board. Excess wire is more likely to be arced to. Be careful not to strain the wire, however.
  • C. Solder the wires together.
  • D. Insulate the connection with some electrical tape.


Primary wires labeled


Solder the primary connector   Completed primary wire assembly



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