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Re: Primary winding

Hi Christopher,

> Original Poster: Christopher Michaelis <cmichael-at-xmission-dot-com>

> I'm trying to use 1/4" copper tubing as my primary coil, but it isn't
> working well. I can't get it to bend smoothly - it looks pitiful.
>
> Would it work to use some really thick copper wire? If so, what guage
> should I aim for?
>
> Thanks
> Christopher Michaelis
> cmichael-at-xmission-dot-com

The primary can be difficult to wind at first. Practice is really the
winner here. But, of course you can use wire. You really should make it a
pretty good size such as 2 or 4 awg. The voltage will travel along the
surface penetrating only slightly into the actual wire. The larger the
radius of curvature, the less likely a charge "point" will develop to arc
to the secondary, turn to turn arcing, or arcing to any nearby metallic
or ground point. Copper tubing really is the perfect conductor for this
circuit. Remember, you will need to tune the coil (usually by tapping the
primary along it's length). Copper tubing makes this easy. Just allow
enough room for whatever connection you use. I would recommend trying
again with the tubing, but think it through mechanically a little more.
You now have the experience of what doesn't work, so do something
different that does. I screwed my first up too and it looked like hell. I
then bought a 50ft roll and gave it a go again. This time it turned out
pretty good. I used ty-wraps to hold it into place. One hole. Brought
ty-wrap up through the bottom to the top, around the tubing, and back
down the same hole fastening underneath. Really a very simple method. If
your using wooden runners, seal them, and try to keep the winding off of
the wood (wood conduction can act like a big resistor and cause massive
losses). If you make a hole just large enough to barely get the ty-wraps
into, the ty-wrap loop will act as a stand-off.

Just some of my thoughts. Here's an old photo of my primary (it has gone
through a few changes since, including more turns - but it shows the
basic idea).

 http://www.geocities-dot-com/CapeCanaveral/Hangar/3108/primary2.html

Bart