Re: drying coil forms

to: Jim

PVC is extremely hygroscopic especially at the surface.  It links with water
molecules in the air to form a surface that "tracks" at high voltages.
That's why other materials such as phenolic and ceramics are used especially
with RF currents at high potentials.

Drying and sealing the surface is a "must" for quality HV work.


Dr. Resonance

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Saturday, December 04, 1999 9:22 PM
Subject: Re: drying coil forms

>Original Poster: Jim DeLillo <jimdel-at-bellatlantic-dot-net>
>Why does PVC have to be dried at all.  Is it not plastic? Is it not
>impervious to moisture?  What am I missing here?
>Tesla List wrote:
>> Original Poster: "Herwig Roscher" <herwig.roscher-at-gmx.de>
>> Paul,
>> >      1) does anybody have any good drying techniques/setups they'd be
>> willing to share?
>> I've (mis)used our sauna for this job. Just below the ceiling the
>> temperature was 95 deg Celsius = about 200 deg Fahrenheit. I've dryed the
>> form for one hour and coated it while it was still warm.
>> Herwig