RE: static spark gaps

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hello,

Check the archives for Richard Quick's blown air gap. I built one for my
dual 15/60 8" coil and blew it with a high power leaf blower and a fire hose
like nozzle. It made a loud ripping noise but it sure worked great. It is
made with two adjustable 1" flat brass dowels 1.5" long on 3/8 brass treads.
The coil could be run for say 45 min or longer with no degradation. Simply
unscrew the dowels and give them a lick with 400 grit. Very easy!

Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Saturday, February 03, 2007 9:20 PM
To: tesla@xxxxxxxxxx
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}
>
>----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
>To: <tesla@xxxxxxxxxx>
>Sent: Saturday, February 03, 2007 1:53 AM
>Subject: Re: static spark gaps
>
>
>>Original poster: FutureT@xxxxxxx
>>In a message dated 2/2/07 1:22:14 AM Eastern Standard Time,
>>tesla@xxxxxxxxxx writes:
>>
>>> >Original poster: Neal Namowicz
>>> ><mr_neal@xxxxxxxxxxxx>
>>> >
>>> >Hi guys,
>>> >I've got a couple questions re: static spark gaps.
>>> >First, what difference does
>>> >it make regarding how much surface area is exposed
>>> >for the gap? Specifically,
>>> >which is better, less or more?
>>
>>
>>Neil,
>>
>>Large surface area is *good*.  It also helps if it's a flat
>>surface area so the spark can move around and heat
>>various areas rather than concentrating the heat at
>>one area.  A cylindrical shape can be used so the
>>spark can at least move along a line.  The worst
>>situation is to use balls or any spherical shape which
>>concentrates the heat at one spot.  Such heating
>>may make it difficult for the gap to quench.  However
>>air flow can help the quenching.
>>
>>Also, can a ssg be
>>
>>> >"over" quenched?
>>
>>
>>It depends on how you define over-quenching.  If you define
>>it as simply too much air to work well, then yes.  In this
>>case it really isn't over-quenching, rather the air prevents
>>the gap from firing steadily.  If you define over-quenching
>>as truly quenching too quickly (for example before the
>>1st notch of RF transfer.... this won't happen.
>>
>>
>>At the
>>
>>> >moment I'm using a blower that was scavenged from an
>>> >old air-hockey table.
>>> >Should I use a dimmer switch to vary the speed,
>>> >since it does seem to move a
>>> >lot of air? Thanks in advance for any advice!
>>
>>
>>Yes, it's good to be able to vary the speed if the dimmer
>>will work well in that application.
>>
>>John
>>
>>> >
>>> >Neal.
>>
>>
>
>
>
>