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Re: [TCML] Form materials, losses, carbon tracking, sealing



Hi Scott:

Styrofoam (mostly dry air) works as a core and is said to be very low loss,
we have used this for conic coils. We also use cardboard concrete forms .
Truthfully I don't think it makes a bit of difference at the low frequencies
involved.

 I doubt that one can seal out moisture in any of these materials. You can
slow down the migration of moisture for a little while but if the coil
is stored in a damp place vapor pressure will do its job and the form will
reach equilibrium with it's environment.

An interesting demonstration of vapor pressure:  Take two pop bottles and
fill one of them 1/2 full of water. Put a nice sized slug of silicone rubber
in the neck of each bottle. Place the empty bottle on top of the half filled
bottle with the openings touching (one bottle inverted) and let them sit on
a window sill where the sun can warm them.

In a few days you will find that moisture has migrated across the silicone
rubber and the empty bottle now has some water in it.
Jared Dwarshuis
On Dec 18, 2007 12:21 AM, Jim Lux <jimlux@xxxxxxxxxxxxx> wrote:

>
>
> -----Original Message-----
> >From: Drake Schutt <drake89@xxxxxxxxx>
> >Sent: Dec 17, 2007 7:19 PM
> >To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> >Subject: Re: [TCML] Form materials, losses, carbon tracking, sealing
> >
> >Hi Scott,
> >
> >I mentioned the idea a while back and the consensus seemed to be that you
> >would have a *very *fragile secondary and it would be very impractical
> once
> >you try to put a top load on it.  I think it sounds like a neat idea, but
> I
> >haven't tried it yet.  Maybe on my next coil?
>
> This is what Greg Leyh did for Electrum (in concept, if not detail).. He
> cast the windings, and then pressure washed the form off.
>
>
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>
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