Re: New 4" coil: R.Hull and CSN, Secondary Varnish

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

Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

This white coating that looks like condensation on the lexan may be some
type of oxidation of the plastic itself due to corona or corona byproducs.
I've noticed this white film in homemade polypropylene capacitors, and it
only happens under AC usage. The caps I made were insert tab wound with 1mil
Hercules "capacitor grade" polypropylene film and at voltages over 1kV at
60Hz. They were dry. The impregnated ones I made failed after the mineral
oil dissolved the film.

KEN


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, September 20, 2002 5:05 PM
Subject: Re: New 4" coil: R.Hull and CSN, Secondary Varnish


> Original poster: "S Gaeta by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<sgtporky-at-prodigy-dot-net>
>
> Yes, I have used it, and it protects against mechanical abuse better than
> polyurethane. However I suspect it is not very good high voltage
insulator.
> I have used it on my replacement secondary for the medium coil. the new
> secondary is exactly the same as the old in every way, except for the
> coating. The old one was coated with polyurethane. Preformance wise there
is
> no difference between the old, and new secondary.
>
> I also used it on my 811A coil, and this is where things get interesting.
I
> used a thin form to wind the secondary. It was 1/16th inch hard plastic,
> probably HDPE, used as a spool for blueprint paper. Even after I coated it
> with the epoxy, I decided that it was still too flimsy, so I enclosed it
in
> a larger diameter PVC pipe, and sealed the ends with clear lexan.
> After I run the tube coil for longer than 5 minutes, I notice that
> condensation forms on the inside of the lexan. This suggests to me that
the
> epoxy may be hygroscopic, and when the secondary gets warm, the water
> evaporates out. Again no failures have occured as a result, but I just
> thought that this should be mentioned.
>
> Also, you have to really mix, and beat this stuff to death for at least
two
> minutes after combining the two parts, otherwise it will not cure
properly.
> It is also worth mentioning that if you apply it over fully dry Minwax
> polyurethane, it will not screw it up.
>
> Sue
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, September 20, 2002 12:57 PM
> Subject: Re: New 4" coil: R.Hull and CSN, Secondary Varnish
>
>
> > Original poster: "Writeme Now by way of Terry Fritz
<twftesla-at-qwest-dot-net>"
> <writeme42-at-hotmail-dot-com>
> >
> > Hi,
> >
> > Has anyone ever used enviro-tex as a secondary coating.
> > Its the stuff they use on bar tops for a rock hard finish.
> >
> > Cheers,
> >
> >         Dan
> >
> snip
>
>
>
>