9″ Secondary – about 1200 turns of 0.67mm wire. The wire is a little thin for a coil this large as I purchased it intending to wind an 8″ secondary. I gave up on the 8″ secondary as locating a suitable form proved difficult. After finally sourcing a suitable 8″ acrylic tube I cleaned it with denatured alcohol. This promptly destroyed it – the surface contraction resulting from the cooling effect of the evaporating alcohol caused the form to fill with microfractures. It was possibly still ok to use, but I didn’t want to risk it. In the end I resorted to the 9″ orange PVC electrical conduit you see here. Hopefully the coupling won’t be too tight. The winding is perfect but unfortunately I rushed the coating so it’s full of runs:
Primary – 10 turns of 1/2″ copper tube (the most I could get from a standard 18m roll). Inside turn is 12″ diameter. Turn to turn spacing is 9-10mm and is far more consistent than the photos suggest.
