RE: Coil form

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dave Hartwick by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ddhartwick-at-earthlink-dot-net>

John Freau and I recently talked about this.

It's hard to imagine that there would be any significant difference in
performance between good ole PVC and the theoretically  best material,
probably Lexan or Lucite.

Significant loss would show up as significant heating in the form itself and
this simply is not observed very often.

Richard Hull recounts heating at the base of his magnifier systems, but some
of these were 2-3" in dia, running multi-kW, producing astonishing output.

I don't think there's anything wrong with cardboard tubes sealed with
varnish, but some may differ on that one.
Dave Hartwick



>
> What's the best material to use for a secondary form?

Calvin,

In many ways, the best material is simple PVC pipe.  Athough
this material absorbs water, this doesn't seem to affect the
performance to any noticeable degree.  Materials such as
polyethylene, polypropylene, and styrene have some better
qualities (lower losses), but are not really necessary unless
special work is being done.  Plexiglas (lucite) is another
material that looks good and is often used, and works well.
One could say that what is best depends upon ones needs.
This is unspecified in this case.

The idea that the form material is super-critical, is basically
a Tesla coil myth, of which many still persist.

The typical coiler is usually well advised to concentrate his efforts
in areas that truly make a difference, if long sparks are the goal

John