Re: Water absorbtion of Gray PVC

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

Original poster: "Harold Weiss" <hweiss-at-new.rr-dot-com> 

Hi Gary,

I had it happen with a 4" the year the dehumidifier broke down in the
basement.  It looked cool while it was happening, with streamers branching
around the form just under the wire.  Another bad material is canvas
phenolic.  I was able to arc thru 10" of it on the 4th of July this year.
Just lucky it was on the primary side of the filter and not the NST side.

David E Weiss

 > Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com>
 >
 > I dare say that I've seen far more successful secondaries built without
 > sanding and Glyptal than I have seen engines without changing oil.
 >
 > Further, the secondary failures that I have seen have all been due to
 > racing arcs or pri-sec arcing, affecting only the exterior surface of
 > the coil, generally polyurethane.  I've never heard of a failure
 > originating on the form _beneath_ the winding.
 >
 > Gary Lau
 > MA, USA
 >
 >
 >  >Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
 >  >
 >  >All PVC is hygroscopic especially when used at high frequencies.  It's
 > best
 >  >to sand interior and exterior, then paint with 3 separate of Glyptal or
 >  >other HV insulation.  Interior sanding is rapidly accomplished by using
 > a
 >  >sanding "flapper" on a dowel (or other extender) on an electric drill.
 >  >
 >  >Some experimenters would say this is totally not necessary.  I recall a
 >  >friend in high school who put over 90,000 miles on his Mustang without
 > ever
 >  >changing the oil . . . . . . . . . . . . . . . .but, I can't recommend
 > this
 >  >procedure.
 >  >
 >  >Dr. Resonance
 >
 >
 >