[Prev][Next][Index][Thread]
PVC, Re. Bert's response on Pyrex
----------
From: Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Wednesday, March 04, 1998 3:25 PM
To: Tesla List
Subject: Re: PVC, Re. Bert's response on Pyrex
In the light of this response, I have a question to ask of Greg Leyh:
> From: Alfred A. Skrocki [SMTP:alfred.skrocki-at-cybernetworking-dot-com]
> Sent: Tuesday, March 03, 1998 3:14 PM
> To: Tesla List
> Subject: Re: PVC, Re. Bert's response on Pyrex
>
> On Wednesday, January 14, 1998 6:10 PM Eleanor Flood
> [SMTP:eflood-at-bellsouth-dot-net] wrote;
>
> > Tesla List wrote:
> >
> > Heck even well
> > > > baked out cardboard tubing that is saturated with polyurethane and allowed
> > > > to dry under heat is superior to glass!
> > > >
> > > <SNIP>
> > >
> > > Alfred,
> > >
> > > Got to disagree with you a bit here, Alfred. The difference in
> > > dielectric loss between PVC and glass is really not all that great...
> > > and Pyrex (at about 30) is actually about 1/4 as lossy as PVC. Even soda
> > > lime glass is only 1-2X as lossy as PVC. While using glass, or PVC for
> > > that matter, as a dielectric in a Tesla Coil tank cap would be quite
> > > lossy, use of this material in a coilform is a significantly different
> > > application. PVC, although quite lossy, makes an excellent coilform due
> > > to it's excellent insulating properties after proper pre-treatment. Its
> > > dielectric loss properties have relatively little practical impact on
> > > secondary Q when compared to other losses in an operating system
> > > (streamers in particular...).
> > >
> > > Jim, your Pyrex coilform will work just fine.. and may actually have a
> > > higher Q than if you wound it on PVC.
> > >
> > > At no loss for words in Illinois... :^)
> > >
> > > -- Bert --
>
> I have to disagree with Bert! First he is compairing PVC to Pyrex which IS
> NOT what I was talking about! I have built secondaries out of; open wood
> frames, cardboard, PVC, polyethylene, plexiglass, vicor glass, and Pyrex
> glass. I found that IF you bake out the cardboard and then saturate it with
> polyurethane it has less losses than ANY glass or even plexiglass and is
> second to Polyethylene! The key factor is the cardboard MUST be totaly
> dried out befor being sealed in with the polyurethane.
>
> > We are now using afore mentioned coated cardboard tubing for secondary
> > coil. Planning a PVC one shortly. Note a reference to proper
> > pre-treatment. Please, how?
>
> Coat the PVC with polyurethane inside and out before winding the secondary
> the coat again when done.
>
> > Plan to make coil as open air as possible by cutting slots lengthwise in
> > PVC about 1/4' apart, this is just a thought, would it be worth the
> > trouble?
>
> NO! If I understand you correctly you are talking about laying the wire in
> precut groves in the PVC, this will increase the distributed capacitance
> and thus lower the secondary output.
Did embedding your new secondary in resins etc have any effect on
frequency and output and if so, by how much?
Thanks,
Malcolm