Re: PVC secondaries

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

Original poster: "Justin Hays by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi Greg and All,

> Some coil plans I have say that when using PVC as a coil form, it 
> should be coated with polyurethane (or similar) BEFORE winding the 
> wire on to reduce losses. Is this really necessary? 

Nah, a couple of mils of plastic on the outside of plastic isn't
going to do anything useful.

> I would have thought it just adds more loss by making the form wall

> thicker.

Maybe in theory, but in real life I'm almost positive it does
nothing...

There are two situations where I could justify coating a coil before
winding. One is if you have a very nice virgin piece of pipe, freshly
sanded, and you're going to be storing it for any length of time. I
would then give it a coat to seal it, so 2 years later all the dirt
accumulated would just wipe off with a damp rag.

The other situation is, if you think winding wire on a smooth piece
of pipe (after coating) is easier than winding on a rough sanded down
piece of pipe. I think it's easier to some degree.

Take care,

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com