RE: secondary insulation

["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>

James,
As Ed Wingate mentions, an optimized coil does not require extensive
insulation. I note that more than a few of Rich Hull's coils were not coated
at all. My one 6" sec is full of black spots, but these are well behaved
when the system is in tune.

It is those experimental phases when things will not be optimized that  are
of concern. Of course, experimentation and tuning should take place at low
power, but it seems that tuning changes at higher power levels making it
difficult to nail it.

The 2 part epoxy idea is interesting, one shall keep in mind.
Dave



Hi list,
    I agree with John, my research has not shown heavy secondary insulation
to
reduce performance. On one of my first secondarys, I used PU varnish (many,
many coats). EVERY time I would get racing sparks, big chunks of varnish
would
be blown off. I have also had 1 racing spark blow a hole in the coating and
burn the wire in half. Now, I use a thick (2) coats of that 2-part stuff.
West
Marine has an epoxy coating that works well, so does HD and Lowes. Now a
minor
racing spark doesn't make a hole in the insulation. As I was writing this, i
was thinking, Why would extra insulation hamper performance? If the wire had
extra thick insulation, the tpi would go down. This however is only a minor
tuning issue. The insulation is not magnetically shielded(mu metal). I don't
see how 1/4 to 1/2 of fiberglas would make much difference. Might trap the
heat.
    In closing, I feel the prevention of racing sparks is the most important
aspect of the secondary insulation. My Tesla coil changes all the time. I
seldom run it the same way twice. Big toploads, big caps (yea Sundog), you
know
let's tinker with it. I keep notes and try never to blow it up the same way
twice.

                                                    Later,

                                                        James