RE: Spark gap construction

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <gary.lau@xxxxxx>

PVC may or may not be suitable, depending upon your power level, how
much thermal mass of copper you have, and how much airflow you have
cooling the pipes.  I've always seen the sparks pretty evenly
distributed along the length, provided the pipes are parallel with
uniform airflow across the length.  I'm personally baffled why there
isn't preferential arcing at the ends where the ROC is less, but I'm
happy for that!

The safety gap could be constructed the same way as the main gap, but
since it (in theory) should only rarely fire, there's no need for it to
dissipate any significant amount of heat.  Quenching behavior doesn't
matter for the safety gap, since it plays no role in the stuff that puts
sparks where they matter.  Balls or roughly spherical drawer pulls are
often used because they can be mounted on a screw and easily adjusted by
turning them.

Precisely correct on safety gap setup!

Regards, Gary Lau
MA, USA

> Original poster: "Black Moon" <black_moons@xxxxxxxxxxx>
>
> Iv seen alot of spark gaps using common copper pipe, and was wondering
if
> PVC pipe would be a suitable support for them, also, do they tend to
arc
> near the edge of the pipe? I was wondering if it might be benifical to
> crimp the ends slightly. As for the safty gap, Should i try and find
some
> balls? or will 3 pipes do just as well? I assume I set the safty gap
by
> running the NST alone with no tesla coil and opening the gap till it
just
> barly arcs over the gap?
>
>