Re: Some first coil questions (preparation of secondary coilform)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "huil888" <huil888@xxxxxxxxxxxx>


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, October 02, 2006 1:42 PM
Subject: Re: Some first coil questions


> Original poster: "resonance" <resonance@xxxxxxxxxxxx

> Do not wash it with water --- this is what you are trying to keep away
> from the coilform.

(Snip)

On the other hand .....
I  wet-sand all of my PVC pipe coilforms using 400 grit silicon-carbide
"wet-or-dry" abrasive paper and water with a few drops of household
detergent added as a lubricant and degreasing agent. With at least 12
secondaries finished this way, I have never experienced any problems of any
kind (most of these have been coated with clear epoxy resin, which would
have trapped any moisture under the coating if any moisture was "adsorbed"
into the surface of the PVC). I use a hard rubber automotive type sanding
block, and sand until a uniform matte surface finish is obtained. In
addition to removing any markings and surface defects, the matte finish
facilitates adhesion of whatever type of finish you may apply over the
windings (varnish, epoxy, etc.).

Obviously, if water, alcohol, acetone, or any other solvent is used for
cleaning it must be allowed to completely evaporate before the winding
process is begun.

Also, if the coilform is heated or warmed for any reason, make sure that you
allow it to return to room temperature before starting the winding process.
PVC has a large coefficient of thermal expansion, and if you start winding
on even a slightly warm coilform, the windings will become very loose when
the form cools and contracts.

Regards,
Scott Hanson