Re: Printed circuit caps ; G10 vs FR-4

To: tesla-at-pupman-dot-com
Subject: Re: Printed circuit caps ; G10 vs FR-4
From: "Steve Cook" <Steve-at-g8cyerichmond.freeserve.co.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Fri, 01 Oct 1999 07:41:07 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme
I connected my PC cap to my TC. The arcs are possibly fractionally longer,
but they are certainly more intense than with my SWCs. I haven't finally
tuned the coil, I hope the arcs will get a bit longer. My key problem at the
moment is getting a better HT supply. At the moment I am using an old
induction coil, and it can't really supply enough current at the required
voltage.

----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, September 30, 1999 1:27 AM
Subject: Re: Printed circuit caps ; G10 vs FR-4


> Original Poster: "Steve Cook" <Steve-at-g8cyerichmond.freeserve.co.uk>
>
> Well I've just made a cap using G10. Value 2n2F, using some of the
offcuts.
> I haven't tried it with a cail, but testing it with a 20kV source, I got
far
> stronger arcs htna I did when I compaired it  with my SWC of the same
value
> (+/- 5%).
> I'm not connecting it to a Tesla Coil tonight as I'm too tired to play
with
> high voltages.
> ----- Original Message -----
> From: Tesla List <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Wednesday, September 29, 1999 2:12 AM
> Subject: Re: Printed circuit caps ; G10 vs FR-4
>
>
> > Original Poster: "ROBERT CRESSLER" <59CREROB-at-menasha-dot-com>
> >
> >
> >
> > >>> <Tesla-at-pupman-dot-com> 09/27/99 09:06AM >>>
> > Original Poster: "Chris McFarlane" <chrismac-at-xtra.co.nz>
> >
> > chris,steve,all,
> > my comments are interspersed below.
> >
> > >>>How does one clearly distinguish between G10 epoxy PCB and FR-4 PCB ?
> >
> > there is no practical method.... however,nearly all g-10 sold in the US
is
> > "g-10/fr4"(nema/fire retardant grade)  to get just g-10 (non
> bromide-nated)
> > is a special
> > order for a couple of areas..... nuclear industry,military,and such.
> > electrical properties
> > are identical.
> >
> > >>>Where can high voltage G10 PCB be purchased from ?
> >
> > check out www.acculam-dot-com or contact me .... I have tons of sources if
> > these can't.
> >
> >
> > >>While a data book mentions G10 as having a dielectric strength of 15
> KV/mil,
> >
> > too high!
> >
> > >>Richard Quick's capacitor info mentions epoxy circuit board as having
a
> > dielectric strength of the much lower value of only 700 V/mil.
> >
> > 400-500volts/mil is closer...... (perpendicular to laminations)
> >
> >  >>but I believe that the G10 & FR-4 grades
> > nope,same thing
> >
> > >>must in fact be very different in their dielectric strengths; so will
> need
> > to be sure of purchasing the correct grade if at all possible.
> > g-10 is glass/epoxy ...... but g-7 glass/silicone is the better (and
> more$)
> >
> > I>> expect G10 will be a more expensive grade, so that the NZD$85
(USD$40)
> >
> > middle of the road in price for the glass series of High Pressure
> laminates
> >
> > Tesla List wrote:
> > > Original Poster: "Steve Cook" <Steve-at-g8cyerichmond.freeserve.co.uk>
> > >
> > > has anyone thought of using printed circuit board for making pulse
caps?
> I
> > > recently came across some surplus double sided G10 board. My data
books
> give
> > > the dielectric constant as 4.5, and the electrical strength as
15kV/mil.
> I/ve
> > > made a small one (0.0005mfd). I ran it at 15kV for an hour, no
> noticeable
> > > heating and no break down. The copper was removed for about 1/2" all
> > round the
> > > edge. I ran a bead of hot glue over the edge of the copper. Capacity
> > works out
> > > at 16pF per sq in. That means that a piece with plates 6.25x10" will
> give
> > > 1nF!!
> > >
> > >
> >
> >
> >
> >
> >
> >
>
>
>