Hi Brandon,
Unfortunately, I did not take pictures as I went along and it's sort
of all finished now. But I can tell you what I did.
First and foremost - there is absolutely nothing wrong with the
secondary I bought. It would have worked fine as advertised, and it
works fine despite my lousy tuning making it arc. I think it's a
testament to the workmanship that it held up against all my newbie
foul ups and I would not hesitate to recommend it to anyone else
building a coil who doesn't want to wind a secondary themselves.
That said, all of my reading suggested to me that having the topload
and ground connections appearing INSIDE the secondary core was
generally a less good design than sealing up the secondary core and
having the connections run along the outside.
What I did was to follow Dan McCauley's design. I bought 2 pieces
of 1/2" thick PVC, each 6" square, from McMaster Carr. (P/N
8747K635) Using a drill press and a circle cutting tool, I cut 2 PVC
circles that would fit exactly inside the secondary tube.
Then, I very carefully pried the wires from the inside of the tube.
The manufacturer had drilled 6 1/32" holes in the side of the tube,
three at the top, and three at the bottom. He then threaded the
secondary wire through those holes in an "S" pattern - from outside
to inside, back outside, and back inside again. Did this both at
the top and bottom. Then he taped the slack to the inside wall of
the secondary with painter's tape.
I put a spot of cyanoacrylic glue at the point where the last turn
of the wire went into the first hole so the secondary wouldn't be
tempted to unravel. Then, using a small sharpened wooden dowel I
pried the wire out of the holes. I then plugged up the holes with a
very small amount of epoxy. Then I wrapped the remaining slack
around the secondary core in a very loose spiral (as I have seen
done in other's coils) and glue it down with cyanoacrylic cement.
Did this for both top and bottom.
Then, I drilled the PVC "end caps". I made one hole exactly in the
center for the top of the secondary, and I put 2 holes in the
bottom. I epoxied into these holes 1/4"-20 nylon bolts so that
their threaded ends stuck outside the secondary core. Once that
epoxy dried enough, I epoxied the PVC plugs into the top and bottom
of the secondary core tube so that they were flush and waited
overnight for everything to dry. Now I had my secondary plugged at
both ends with PVC, and with threaded nylon bolts sticking outward
from both sides.
On the bottom of the secondary, I stripped the wire with a bit of
sandpaper and then soldered the secondary wire to a small square of
copper plate which I epoxied to the outside of the secondary tube
below the last tight turn of the secondary windings. On the top, I
epoxied a copper disc to the PVC and then soldered the top wire to it.
Thus, the top of my secondary was now an exposed copper disc
connected to the top of the secondary. On the bottom, I had 2
threaded nylon rods sticking out and the copper plate epoxied to the
side.
I mounted the secondary to the space in the center of my primary by
drilling 2 holes and inserting the nylon bolts through the holes. I
made the ground connection by soldering a piece of 12ga copper wire
(romex) to another copper plate, and pressure fitting it against the
plate on the secondary with nylon wire-ties. Not so elegant, but
functional.
On the top, I just slid the toroid onto the single nylon bolt and
it made contact with the copper plate on top.
I'm not sure that sounds easy, but it was. It just took a whole lot
of time, and honestly, I probably could have done a better job of it.
If desired, I'll take pictures of the final result and post
somewhere. I just didn't think to take illustrative pictures as I
was going along.
All the best!
Joe
On May 31, 2010, at 11:00 AM, tesla-request@xxxxxxxxxx wrote:
Hi Joe,
Could you go into greater detail on how you performed your
secondary makeover? Possibly post some pictures if you already have
them?
Thanks a lot,
Brandon
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