The ZVS induction board comes with a work coil that is too big for brass case annealing in my opinion. I wound a replacement using smaller 1/8” (3mm) OD copper tube to better concentrate the magnetic field on the case shoulder and neck. The inductance of the coil is important to keep the system operating at an efficient frequency. I suggest starting with the design I have below and tweak it if you need.

The 1/8” tube gets soldered into the supplied larger copper as shown below for easier connection to the ZVS board and water hoses.

New coil:

• 28mm ID – wrap the 1/8” OD copper tube around a 28mm OD tube, socket, whatever you can find.

• Wrap 7 ½ turns with an air gap in between each turn – if you can find some insulating sleeve like on the picture below, that’s even better. Some have enameled the tubing to give insulation between the windings.

• Finished coil height is about 30mm