Re: New coil and Wood

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

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

Hi Dan,

I remember reading somewhere, (Bill Wysock's site I think) that Sitka Spruce
is the best wood to use for HV use, and is used as spacers in large xfmrs.

David E Weiss

 > Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com>
 >
 >
 >
 > I've actually seen a number of MIL-type high voltage assemblies (mostly
 > in airborne radar systems) built around 1970's - 1980's that use a
 > considerable amount of wood in them.  When I inquired about this, I was
 > even told there is a MIL-SPEC
 > regarding wood and general / high voltage use.
 >
 > Dan
 >
 >
 >  > "There's a long and illustrious history of using properly
 >  > prepared wood
 >  > in HV
 >  > devices.  Heat it to dry it, immerse it in something to keep from
 >  > soaking up
 >  > the water (like melted paraffin (wax to those of you in the
 >  > rest of the
 >  > anglophone world)), etc. (Hmm, a hydrocarbon/cellulose composite
 >  > material..
 >  > conceptually, not that far from fiberglass reinforced
 >  > plastic, when you
 >  > think about it)
 >  >
 >  > Other popular insulating materials in "pre plastic" days: sulfur,
 >  > ebonite
 >  > (whatever that is...I'm sure one of the historical mavens on the list
 >  > will
 >  > tell us what it is)"
 >  >
 >  > The waxed wood is great stuff and I use it frequently.
 >  > One advantage
 >  > is that soft wood like pine, when waxed, can be machined with
 >  > finer cuts
 >  > than in the natural state.  One word of caution though.
 >  > Melted paraffin
 >  > is dangerous stuff, both from the standpoint of fire and damage to the
 >  > human body.  One further note is that it's easy to get the
 >  > stuff so hot
 >  > that it will char wood.  Best temperature seems to be a bit below that
 >  > point; leave the stuff in until it quits bubbling and then
 >  > remove it and
 >  > cool it.  Bear in mind that most wood shrinks several percent as the
 >  > water is driven out, so if dimensions count do your treatment before
 >  > cutting things to size.
 >  >
 >  > Ed
 >  >
 >  >
 >  >
 >
 >
 >