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Re: Secondary Winding Done

Inspired by Chuck Curran's description of his secondary winding experience, I
thought I would recount my story, as I was engaged in the same activity this
weekend.

I had purchased the 6" acrylic form, 27" in length last November.  It wasn't
until just after Christmas that I found the time to cut out the plywood end
plugs to hold the steel support rod that was the basis of my manual
winding rig.  I constructed the plugs so that they tapered inward slightly
for a tight fit in the ends of the tube.  After drilling the center
holes for the support rod, I tapped the plugs gently into place (or
so I thought).  After constructing the jig to hold the spool of magnet wire,
I set everything up at a comfortable height and prepared myself for an hour
or so of winding.  To prepare the dusty surface, I wiped it down with a rag
moistened with alcohol.  As I set the bottle on the floor, I heard what sounded
like a soft crackling noise.  Looking at the tube, I watched in morbid 
fascination as a network of tiny cracks appeared at each end of the tube, 
progressing the full length until they met.  At this point, the tube split and
fell crashing to the floor.  Arghhhh......

Apparently my "light tapping" of the end plugs had produced micro-fractures
which became macro-fractures after the cooling effects of the evaporating
alcohol.

I ordered a few more lengths of tube and waited.  This time I fashioned the end
plugs to just fit into the open ends of the tube and did not taper them.  I then
used a few dabs of hot glue to hold them in place.  This worked fine.

I found that the winding process worked best if the wire being fed from the
supply spool was arranged such that the wire hit the form so that it crossed
the windings that were already in place.  It was an easy matter to apply 
tension with my thumb to keep the winding tight and firmly in place against the previous winding.  I was able to wind without even looking at the form after a
few minutes of practice.

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I finished up the form with two coats of clear, two-part epoxy resin.  As the
varnish on the wire was black, the coil looks as though it were painted
with a thick, shiny black paint.  It's really quite attractive, in a tesla-coil,
hi-tech sort of way.  Even my wife and children admired it!

I finished off with epoxying the plexiglass end gaps on, the one on the 
grounded end with a tiny hole in the center for pressure equalization.
I have yet to install the grounding plate.

In my opinion, the acrylic form is the way to go.  Aside from my initial
mistake, I found that the whole process (which I was dreading) was actually
very enjoyable.  Just keep in mind that acrylic is not as strong or as
flexible as PVC.

Regards,

Don Froula

PS - Richard Quick's grounding plate instructions specify that the base wire
from the coil should be soldered to the back of the terminal plate, after
flattening out the wire with a hammer.  Can anyone think of a reason not to
just solder the wire to the top front edge of the plate and epoxy into place?

Thanks,

DF