If the pipe were 100% PVC, there would be no problems. But with either
thin or
thick wall PVC, one runs a small risk of there being a spec of conductive
flotsam just beneath the outer surface that could cause a short between the
potential of a few turns. If you stick a light bulb inside a piece of
thin wall
pipe you may see this.
But I've used nothing but PVC pipe and never had a problem. For the
majority of
us that pay for pipe, PVC is the only economical choice. I don't know if
thin
or thick walls alter the risk of conductive flotsam. I was able to do the
light
bulb thing on a piece of very thin-wall 4" SDR pipe, but I've not seen 6"
pipe
thin enough to be translucent. Odds are it will be just fine.
Regards, Gary Lau
MA, USA
>
> The only credible reported difference in secondary form materials so far as
> losses are concerned have been in the paper-based "Sonotube" concrete
forms.
It
> wasn't the paper, it was the unknown binder that was believed to be
responsible
> for the losses, and even then, the losses were theoretical based on (I
think)
> ringdown measurements. It was felt that such losses might only be an
issue on
> CW or solid state coils. The many, many pig-powered Sonotube coils
that work
> just fine are evidence that it's not a deal breaker.
>
> There was also a report that PVC pipe often contains random debris that
in at
> least one instance, proved to be conductive, causing a secondary
short. PVC
> itself is just fine though.
>
> I think there would be no measurable performance difference between the
> materials you mentioned. I would base the choice on material strength,
> machinability, color (aesthetics), will glue and polyurethane stick to
it, and
> weight. I would choose the thinnest wall that's structurally adequate,
but
only
> to minimize weight.
>
> Regards, Gary Lau
> MA, USA
> > Hi all.
> >
> > I have just struck a little bit of gold, I now have more or less
> > unlimited supply of
> > coil forms in glass fabric, cotton fabric and paper. The resin in
> > these forms are some of the
> > following: Phenolic, Epoxy, Melamine, Silicone and Polyester.
> >
> > Are they all good for winding coils on or are there some that i should
avoid?
> >
> > Thanks!
> > /Matt
> > www.tesla.nu (in Swedish)