Re: My Secondary
Subject: Re: My Secondary
From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
Date: Wed, 10 Apr 1996 12:07:14 -0500
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>Date: Tue, 9 Apr 1996 20:04:58 +0700
>Subject: My Secondary
>From: "Scott M. White" <smw12-at-po.cwru.edu>
>I've been lurking a while learning about Telsa coils but unfortunately I had
>already finished my secondary when I actually learned what I should be
>doing. I had slighly more entusiasm than brains and so I wrapped the coil
>around a 4' long cardboard tube with 8.5" diameter. I did not paint it with
>any kind of finish to make it more of an insulator. I also made a rather
l>arger mistake in using (and this is the kicker!) #34 wire. So now I have a
>4' long 7000 wind inductor and I was wondering if there is any way to make a
>working tesla coil out of this or do I just have a big piece of junk. Any
>suggestions would be grealy appreciated.
Although this coil will not be optimum for a spark gap oscillator TC
running at critical coupling, it may provide reasonable service in a
vacuum tube CW ocillator powered TC. You'd want to run rather tight
coupling between the primary and secondaries where transformer action
based on turns ratio would predominate. Your high turns count will
definitely help you here. You won't need a big storage terminal on
top of this type of system either. Just a 1/4 inch bolt electrode
poking out of a ceramic insullator at the top of your secondary will
You must have a lot of patience and a very steady hand to wind such a
large coil with #34! I've broken this stuff with just the tension of
feeding it over my finger!
I think you should try to moisture seal that coil from humidity
effects. Pick a really dry day with low humidity, drive out traces
of moisture by warming the entire unit with a hair dryer or hot air
heat gun, and coat the inside and outside surfaces with varathane.
The cardboard shud really drink this up and it will prevent
infiltration of moisture in the future. This is not going to be that
easy a job to coat the inside but perhaps you can work with a brush
from both ends. More than one coat probably would'nt hurt either.
Anyone else feel free to jump in here?!
Happy coiling!, rwstephens