(spacing of windings)RE: Need Secondary wire source

["LOCKWOOD, Chris J." <clockwood-at-orbeng-dot-com.au> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Has anybody tried winding a secondary using threaded PVC?

Its pretty easy to cut a thread into a piece of pipe using a lathe. It
wouldn't take that long, and would give an accurate wire spacing. It might
be an advantage to provide a small spacing, to allow the insulation coating
to flow between the windings- providing better insulation between turns, and
greater mechanical strength.

It would also be less likely for the wire to get messed up during winding-
since they fall into guide slots.

I was thinking of making a new coil with a very small spacing between the
windings (using #26 wire, and a < 0.1mm gap) -coating with a thickish layer
of epoxy resin. This would hopefully provide a superior layer of insulation
compared to enamel, and the epoxy would run freely into the thin gaps
(especially when heated)...

Is the PVC pipe form likely to break down if I dont pre-coat it?

Should I bother?

Chris

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, August 03, 2000 8:38 AM
To: tesla-at-pupman-dot-com
Subject: Re: Need Secondary wire source


Original poster: "Ed Phillips" <evp-at-pacbell-dot-net> 

I've wound coils with both monofilament spacing and very heavy woven
cotton thread spacing.  I forget the name of the latter, but left it in
place.  After winding the coils (by hand, mounted on very very crude
centers) I gave them a very light coat of thinned urethane varnish. 
When that had dried I pulled the monofilament out and had a very neat
space-wound coil.  Diameter was 4", winding length 18", and wire sas #28
single formvar. Bottom line was that, in accordance with the comment
below, it certainly wasn't worth the bother, and the lower secondary
inductance ran the resonant frequency higher and the things didn't work
as well as close wound.  Don't bother!
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