Re: static spark gaps

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi Frank, all,

I have to jump in here and exhibit partial disagreement
on the tungsten carbide. I say partial disagreement be-
cause pure tungsten is definitely the BEST choice for
SG electrode material but tungsten carbide WILL work
in the absence of pure or thoriated tungsten. I original-
ly used tungsten carbide drilling blanks for the SG elec-
trodes of my ARSG in my Green Monster coil:
http://www.teslauniverse.com/members/drieben/
with reasonable success. I did note that the tungsten
carbide did not dissipate heat as well though (the
brass electrode supports would get VERY hot
after a couple of minutes of operation), but once
I changed over to pure tungsten, the heat was
more quickly dissipated due to the superior thermal
conductivity of pure tungsten over tungsten carbide.
A search of the archives will also show a number
of coilers have had success with tungsten carbide
SG electrodes in their big coil systems.

David Rieben

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, February 03, 2007 11:19 PM
Subject: Re: static spark gaps


> Original poster: Frank <fxrays@xxxxxxxxxx>
>
> Hi All,
> Silver was used in early spark gaps without much success. The silver
> vaporizes and oxidizes rapidly and your gap will fire for a short
> time and then start sputtering.
> It gives off a beautiful green blue flame tho!
> The only way you could use silver with limited success is to water
> cool the gap and use low currents. Not suited for SGTC's unfortunately.
>
> Tungsten carbide does not work well either, you gap gets very hot and
> does not spark well.
>
> Pure tungsten or thoriated tungsten works the best.
> Some folks use TIG welding electrodes with good success, it just
> depends on the type of compound they used to make the electrode.
>
> Frank
>
> At 05:51 PM 2/3/2007 -0700, you wrote:
> >Original poster: "James Howells" <james@xxxxxxxxxxxxxxxxxxxxxxx>
> >
> >May I join this thread?:
> >Many people have mentioned Tungsten electrodes .... are these
> >tungsten or tungsten carbide ?
> >
> >If  as suggested below a flat surface is best: what is the general
> >opinion on using two silver faced contact breaker studs ( salvaged
> >from a fork lift truck) as the static gap ( low power = ignition
> >coil job- no pigs!)
> >
> >They are brass , 1/2 dia. and have very thick silver plates* as the
> >faces .* plates not platED.
> >
> >Will the silver be good ... because of the conductivity , or bad
> >because it's easily oxidised & eroded
> >
> >
> >Thanks
> >
> >James - in Staffordshire,  England
> >www.SpamJab.com {UgzndUInruKjv2Cy9r}
> >