Re: winding the secondary

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jeff,

On 1 Sep 2001, at 11:50, Tesla list wrote:

> Original poster: "Janet Johnson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jpjmassage-at-earthlink-dot-net>
> 
> Hi list,
> I am getting ready to wind my secondary and I have been reading different
> approaches.  Brent Turner's book says if you use a plastic (PVC) pipe, just
> sand it and clean it, wind it and seal it with "several light coats of a
spray
> acrylic or lacquer."  So he doesn't say it's necessary to seal it before
> winding it.  Richard Quick on the other hand, says to bake it in an oven
> overnight after wet sanding it and then coat it with polyurethane for several
> hours before winding it.  My questions: if you just dry sand the pvc do you
> need to worry about drying it?  How smooth does it need to be (I haven't
gotten
> all the scratches and nicks out of it after sanding it quite a lot)?  Do you
> coat it again after winding?

I simply wouldn't bother with all the drying etc. etc.  The 
difference in unloaded Q that will result won't be worth the effort. 
One of my coils is wound on a piece of thickwall drainpipe which was 
lying around outside in a merchant's yard for months. I simply wound 
it and used some varnish to hold the windings in place (it is 
spacewound). Unloaded Q on a damp day clocks in at about 300.

Malcolm