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RE: Connecting pipes together for primary?

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>


I have the same experience as Gary.  My primaries are 1/4" copper tubing
spliced together at multiple points w/ 1/4" ID by 1" lg brass tubing and
plumbers solder.  My small coil resonates at 383 khz and produces 16 to
24" streamers.  My medium size coil resonates at 100 khz and produces 48
to 60" streamers.  If the solder joints cause big losses, it is
certainly not having much of an effect on my results.


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

I hate to tell folks to use exotic solutions when every day materials
are perfectly sufficient.  When splicing primary tubing, the gap between
the copper segments is what, .001"?  Do you have experience or data to
show that a splice made with tin/lead is measurably or functionally
different than one made with tin/silver?

I think the often-cited fear of skin effect losses in non-copper
conductors is not applicable to Tesla coils.  My experiments of primary
conductor AC resistance over 40KHz to 800KHz showed no significant
difference between an aluminum conductor and copper conductors of
similar gauge.  There are other good reasons to choose copper over
aluminum - more reliable tap connections and the ability to solder - but
skin effect losses due to Al vs. Cu would appear to be a non-issue.

Have you ever tried to take a coil of #6 solid Cu wire wound on the
hexagonal spool at Home Depot, and re-form it into a smooth spiral? That
stuff is a b***h to work with!  Copper tubing is much easier to form,
and easy to splice.  When splicing, I like to use a 1" length of brass
#10 screw or threaded rod inside the two pieces of 1/4" tubing.

Regards, Gary Lau

 > Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>
 > As long as you use a torch and silver solder no problem.  Regular
solder  > will offer high resistance to RF currents with it's lead/tin
content.  >  > Sometimes it's easier to just use #6 AWG ground wire,
solid, from Home  > Depot.  >  > After conducting a "scrap wire" tuning
session, remove the wire, measure it,  > and add two more turns length,
then you can get the Home Depot wire cut to  > the correct length.  >  >
Dr. Resonance