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Re: Water absorbtion of Gray PVC - sono tube idea



Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Paul,

You don't want to use carbon fiber since it is sort of conductive at 
500,000 volts ;-))

But Greg Leyh used a giant sonotube form for the Electrum in which he 
coated the tube with fiberglass and then power washed the cardboard away 
just leaving the fiberglass tube.

http://www.lod-dot-org/electrum.html

Cheers,

         Terry




At 02:33 PM 12/9/2003, you wrote:
>Watching discovery the other week ( think it was discovery) they had the
>rocket challenge, where the showed how they built the rockets but wrapping
>carbon fiber around a sono tube then curing the carbon fiber, and soaking
>the whole thing in water to remove the cardboard.
>
>Now at first i though cool a carbon fiber secondary form! but then i though
>carbon humm . . .
>
>At any rate why not wrap the mag wire around a sono tube heavily coat as
>most do with lacquer or enamel, then remove the card board and wa la AN AIR
>CORE.
>
>Just my ramblings
>Paul
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Tuesday, December 09, 2003 9:48 AM
>Subject: RE: Water absorbtion of Gray PVC
>
>
> > Original poster: "David Trimmell" <humanb-at-chaoticuniverse-dot-com>
> >
> > Hi, I have to agree with Dan here. In all reality a <3Kw coil can easily
> > be wound on un-treated PVC with many years (many hours of total run
> > times) of use. I will add, though, that a quick rough up with a coarse
> > sand paper, and then hitting the coil with a heat gun to get it warm and
> > immediately spraying it with a acrylic sealant, doesn't hurt!
> >
> > Regards,
> >
> > David Trimmell
> >
> > -----Original Message-----
> > From: Tesla list [mailto:tesla-at-pupman-dot-com]
> > Sent: Monday, December 08, 2003 5:09 PM
> > To: tesla-at-pupman-dot-com
> > Subject: RE: Water absorbtion of Gray PVC
> >
> > Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com>
> >
> >
> > Although your concerns and comments are valid, its really not necessary
> > (especially for the mere hobbyist)
> > to perform this long process of pre-treating a PVC or other hydroscopic
> > forms prior to winding.
> >
> > Although your intent is good, i feel your comments may actually
> > discourage some beginners by making them believe
> > they need to go through this seemingly overwhelming pre-treatment
> > process.  This is especially true considering the
> > comments come from the two most experienced tesla coil firms, Resonance
> > Research Corporation and KVA Effects.  The beginner
> > may believe these firm's comments may hold more water so to speak than
> > the other people on the group.
> >
> > The important points I think should be made are the following:
> >
> > 1.  Yes, hydroscopic secondary forms such as PVC will benefit from a
> > pretreatment process as described below especially
> > in higher power tesla coils (5kW + )
> >
> > 2.  For most small power coils, there is no need to pre-treat the PVC
> > secondary.  This is based on the experience of many of the members of
> > this list including myself.  I'm sure if you took a poll, the number of
> > people on this last that go through the elaborate process of
> > pre-treating a secondary prior to winding will be greatly outweighed by
> > the "just wind it" and go people of the list!
> >
> > Many people on this list will claim sonotube or other cardboard forms
> > are the worst possible material for a secondary form
> > and should be avoided at all costs.  However, the best coils i've ever
> > seen were built with cardboard forms.
> >
> > Dan
> >
> >
> >
> >   > TCML,
> >   >
> >   > I have to back Dr. Rez on this one guys... We use PVC and
> >   > fiberglass forms.
> >   > We have accumulated hundreds of hours of run time on a dozen
> >   > or more PVC
> >   > coils all above 10kW. We have a really burnt PVC form we keep
> >   > in the shop as
> >   > a trophy...
> >   >
> >   > Sand, bake*, seal...
> >   >
> >   > Sanding breaks up the surface. HV arcs love to travel down
> >   > smooth surfaces.
> >   > We use coarse grit and leave the final finish rough. After
> >   > surface prep and
> >   > careful and gradual baking with tungsten strip heater, seal
> >   > the PVC with
> >   > commercial HV varnish. There's more to the process but those
> >   > are the basic
> >   > steps hobbyists should follow.
> >   >
> >   > Will you coil work the same if you don't follow these steps:
> >   > sure! Same
> >   > applies to O-rings and spray-on foam insulation.
> >   >
> >   > * don't over do this step. 20 degrees above ambient for two
> >   > hours is all
> >   > that is necessary IMO. If you use heat lamps, spread them
> >   > out, put them on a
> >   > variac and don't put them too close. "Hydroscopic" doesn't
> >   > mean it's full of
> >   > water and you have to dry it out.
> >   >
> >   > Jeff Parisse
> >   > kVA Effects
> >   > www.teslacoil-dot-com
> >   >
> >   >
> >   >
> >   > snip...
> >   >
> >   > 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.
> >   >
> >   >
> >   >
> >
> >
> >