Sonotube HV properties

To: tesla-at-pupman-dot-com
Subject: Sonotube HV properties
From: lod-at-pacbell-dot-net
Date: Tue, 18 Feb 1997 22:22:28 -0800
Subscriber: lod-at-pacbell-dot-net Wed Feb 19 22:05:48 1997

Ed Wingate wrote:

> Bert,
> 
> Although I agree with Richard that cardboard is definitely not the ideal
> material to seek for secondary forms, I used 20" Sonotubes for the
> secondary forms on my half wave twin coil and have not had any voltage
> breakdowns in over three years of operation. The only coating used on
> the windings is two or three light coats of shellac to hold the wire in
> place, not for insulating purposes.

Hi Ed,

A lot of people have told me that Sonotubes are patently unsuitable for HV work, 
that they absorb moisture, the ink conducts, etc. 

But your half-wave coil success clearly shows that these tubes can be used for 
high-performance TC applications.  Could you tell us the brand of paper tube 
that you used to make your coils?

-GL