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Re: [TCML] Form materials, losses, carbon tracking, sealing



I had considered doing something like that with a wooden base form for a
fiberglass sock.  I have a friend that makes fiberglass rocket bodies, but
he doesn't make them much larger than 2" diameter.  I have seen fiberglass
tubes sold as large as 12" diameter.

I would imagine if you wanted to have as little secondary "frame" material
as possible, you'd need to make it out of some non-brittle binder (like the
spar varnish mentioned above) but you'd probably have even better luck if
you also had some stiffeners in there somewhere like fiberglass or prehaps
thin strips of phenolic to serve as "bones" for your secondary?

Tim

On Dec 17, 2007 7:19 PM, Drake Schutt <drake89@xxxxxxxxx> wrote:

> Hi Scott,
>
> I mentioned the idea a while back and the consensus seemed to be that you
> would have a *very *fragile secondary and it would be very impractical
> once
> you try to put a top load on it.  I think it sounds like a neat idea, but
> I
> haven't tried it yet.  Maybe on my next coil?
>
> good luck,
> Drake Schutt
>
> On Dec 17, 2007 9:07 PM, Scott Bogard <teslas-intern@xxxxxxxxxxx> wrote:
>
> >
> > Has anybody ever tried building a coil on a cardboard form, applying
> > many, many coats of thick urethane or epoxy or whatever, and then
> > removing the cardboard form alltogether?  From what I understand of the
> > sonotube cardboard forms, they are meant to peel off once the concrete
> > is dry, so would it be possible to have a very delicate formless coil if
> > great care was exercised during it's construction.  Please note, I do
> > not consider myself careful enough to try this, I am simply curious to
> > see if anybody else did.
> >
> > Scott Bogard.
> >
> > Lau, Gary wrote:
> > > I think it was someone else who noted a failure on a new PVC
> secondary,
> > and failure analysis showed that there was something embedded within the
> > plastic. I think it may have been Terry that investigated the contents
> of
> > PVC forms, but not certain.  If one takes a piece of relatively thin
> wall
> > PVC pipe (4" SDR) and you put a light bulb inside, it's easy to see bits
> of
> > flotsam and jetsam.
> > >
> > > As a separate issue, Terry performed a "ping" test to investigate
> > secondary properties, and found that secondary coils wound on paper
> concrete
> > forms were significantly lossier than PVC forms.  But the experience of
> many
> > suggests that at least for spark-gap coils, concrete forms do work,
> perhaps
> > because when using a pole pig for power, the losses in the form are
> small by
> > comparison.  I think I recall some say that when used for CW coils, tube
> or
> > solid state, that the losses in concrete forms do become a problem.  Not
> > sure about disruptive DRSSTC's, but probably best to stick to PVC there.
> > >
> > > Regards, Gary Lau
> > > MA, USA
> > >
> > >
> > >> -----Original Message-----
> > >> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> > >> Behalf Of Barton B. Anderson
> > >> Sent: Friday, December 14, 2007 8:51 PM
> > >> To: Tesla Coil Mailing List
> > >> Subject: Re: [TCML] Form materials, losses, carbon tracking, sealing
> > >>
> > >> It's not the ink but the particles that become embedded within the
> > paper
> > >> (metallic particles) when it's made. I think Terry Fritz did a study
> on
> > >> this to find areas of metal clumps within the cardboard. Obviously,
> > >> moisture absorption is high so sealing is certainly recommended.
> > >>
> > >> I personally haven't had any noticeable problem with paper concrete
> > >> forms, but I can understand the apprehension. What I don't like about
> > >> the forms is end cap mounting. Also, if it falls it's easily damaged
> > >> (like when your wife opens the garage door and the back of the door
> > hits
> > >> the top of the coil! Yes, I know, my fault).
> > >>
> > >> Take care,
> > >> Bart
> > >>
> > >>
> > >>
> > >> Dr.Hankenstein wrote:
> > >>
> > >>> I'm not so sure if using paper concrete forms is such a bad idea if
> > you take care
> > >>>
> > >> to make a careful selection and remove the "inked" layer, properly
> dry
> > and varnish
> > >> the form. For example, here is a picture of a 12" by 48" coil built
> by
> > Dr. Spark
> > >> producing about a 8 foot spark. This coil uses a cement form and has
> > produced
> > >> arcs in excess or 14 feet with no problem!
> > >>
> > >>> http://www.drspark.org/images/wwt2007/1281.JPG
> > >>>
> > >>> Spark on!
> > >>>
> > >>> Woo
> > >>>
> > >>>
> > >> _______________________________________________
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> > >>
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> > >
> > >
> > >
> >
> >
> > _________________________________________________________________
> > i'm is proud to present Cause Effect, a series about real people making
> a
> > difference.
> >
> >
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