Re: "best" former material?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Chris Snyder by way of Terry Fritz <twftesla-at-uswest-dot-net>" <csnyder-at-ga.prestige-dot-net>

Anybody thinking of using polypropylene,
    Just a heads up to anyone who's going to use polypropylene...  I'm just
about finished winding a secondary on polypropylene... The one bad thing I
can say about it is that it is nearly impossible to bond to.  Tried all
kinds of epoxies, they just fall right off of it. Most epoxies even say not
for use on polypropylene. Luckly, polyeurethane holds well enough to keep
the windings on, but a few flexes of the form and they'll fall right off. :P

Chris Snyder


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, March 10, 2001 2:56 PM
Subject: Re: "best" former material?


> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<FutureT-at-aol-dot-com>
>
> In a message dated 3/9/01 9:15:19 PM Eastern Standard Time,
tesla-at-pupman-dot-com
> writes:
>
> > John:
> >  What is it about the materials you mentioned that make them suitable
for
> > coil
> >  secondary
> >  formers?  Is it their dielectric constant, lack of water absorption, or
> what?
>
> Ray,
>
> I mentioned Polystyrene, polypropylene and polyethylene for their
> low dielectric loss at TC frequencies.  Yet their cost is reasonable.
> But in general, there is often too much concern about losses in
> a secondary form.  One of the things that makes polypropylene
> and polyethylene good is they don't carbon track anywhere as
> much as PVC.  In any case, the losses in these forms won't
> noticeably affect your electric bill either way.   I wouldn't bother
> with the Pyrex, it's lossy, heavy, brittle, etc.  If I had to chose
> from a bunch of selections like that, I'd chose polypropelene
> or polythylene for their low low losses, and resistance to carbon
> tracking and burning up.  Styrene is low loss, but carbon
> tracks.  The advantage of styrene is it may be a little more
> rigid.  I would probably give more weight to rigidity than electrical
> loss, because the electrical loss is so low anyway.
>
> You could use the 3 or 4 bars of polystyrene to hold the winding,
> but it won't make the sparks longer, and it won't save on your
> electric bill.  Why do you think that the losses are significant,
> and worth taking such measures?  The bar method has certainly
> been used by a number of coilers, usually when a large form was
> not available or was too costly or heavy.
>
> John Freau
>
>
>
> >
>
>
>
>