Re: Puncture voltage

> Date:          Sat, 24 Aug 1996 22:42:04 -0600
> From:          Tesla List <tesla-at-poodle.pupman-dot-com>
> To:            Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject:       Re: Puncture voltage
> Reply-to:      tesla-at-pupman-dot-com

> >From rwstephens-at-ptbo.igs-dot-netSat Aug 24 22:02:40 1996
> Date: Sat, 24 Aug 1996 15:25:52 -0500
> From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Re: Puncture voltage
> >>From al263636-at-sal.itesm.mx.pupman-dot-comFri Aug 23 22:42:41 1996
> >Date: Fri, 23 Aug 1996 09:49:29 -0500 (CDT)
> >From: Jorge <al263636-at-sal.itesm.mx.pupman-dot-com>
> >To: Tesla-List <tesla-at-pupman-dot-com>
> >Subject: Puncture voltage
> >Hi,
> >	Im fairly new on building Tesla Coils, i recently built a small 
> >	one, it uses a 9000, 30ma neon sign transformer. My problem is 
> >	with the cap, i live in a small town and theres no where i can 
> >	get the poly to build the caps, so instead i used 1/8" window 
> >	glass, i sumerged the cap in oil and i also spreaded some in 
> >	between the plates, my question is ? Can the cap hold and for 
> >	how long ?.
> >	
> >	Could some one please answer, i know this must be an easy 
> >	question for some of you, but im new at this some and im a 
> >	little nervous turning on the coil and have the cap blow up. 
> >	Thanks
> >	Jorge Fuentes						
> >**********************************
> >*    "World without end,         *
> >*     From beginning to the end, * 
> >*     We are alive,              *
> >*     Forever."                  * 
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> Jorge,
> When we coilers refer to a glass capacitor 'blowing up' it is just a 
> figure of speech.  There is no explosion,... well hardly ever, and most 
> of the time the house can  be rebuilt almost as good as new!
> I'm just pulling you leg:)  There is no explosion danger with the 
> modest energy stored in a typical tabletop system, just the annoyance 
> that your cap will have to be rebuilt.  If you have it immersed in a 
> transparent plastic container you will see a bit of a light show, 
> bluish colour light coming from in between the plates where there may be
> trapped tiny air bubbles.  Keep your run times short, 5 to 10 seconds and you
> will be probably OK.  Those little blue lights are localized heating 
> points working on the surface of the glass.  The failure mode is when 
> you see a whitish green light come out the edge of the glass plate as 
> the glass itself punctures from localized thermal runaway.  Usually 
> this is accomapied by a click noise as the sheet of glass in the pack 
> fractures into two or more sections.  The oil bath and sandwhich with 
> the other sheets prevents this glass from going anywhere.
> An alternate to a glass plate and aluminum foil cap is one made with 
> beer or wine bottles.  Fill them with a saturated solutuion of water 
> and table, or rock salt to about 2/3rds full.  Place all these 
> bottles in a plastic tub which is itself filled with the same brine 
> solution so as the level in the outer tub, bucket, etc, is the same 
> as the level inside the bottles.  Loop a piece of bare copper wire, 
> (#14 works) into all the bottles making good contact with the 
> saltwater.  This becomes one terminal of your capacitor.  Run a 
> length of the same type bare wire around inside and below the surface 
> of the saltwater in the tub.  This is the other connection.  You can 
> easily change the capacitance of this capacitor by adding, deleting 
> bottles, or by playing with the level in the outer tub.  Once you've 
> got the system tuned, you can pour cooking oil over the surface of 
> the saltwater, both inside the bottles and in the outer bath, just 
> enough to completely cover the surfacwe.  This will keep your water 
> from evaporating, thus detuning your capacitor.  
> If you use 12 ounce common beer bottles, I think I would start with 
> 12 bottles, but this is just a guess as I've not built one.  Anyone 
> out there know the capacitance of a beer bottle?
> Good luck!
> rwstephens
Your idea of using bottles and salt water is a very old one. Usually 
champaine bottles are the ones of choice since the glass is thicker 
and the bottles are larger. The bottom is also thicker than the sides 
which produces a good floating action. However, where are you going 
to get that many champaine bottles?

Chris Singletary
President - Lightning Software
Believe that you CAN accomplish the impossible and you shall.