Re: More rotary gap questions...

Subject:       Re: More rotary gap questions...
       Date:   Thu, 24 Apr 1997 13:25:27 +1200
       From:   "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Organization:  Wellington Polytechnic, NZ
         To:   tesla-at-pupman-dot-com

Hi Ed (Wingate),

> Hi Alfred and all,
> I have just one small statement. Please don't confuse tungsten carbide
> with metallic tungsten, they are two very different materials with two
> very different uses. Tungsten carbide is used for cutting tools and must
> be machined with a soft green (silicon carbide) wheel or diamond wheel
> and is not a good material for spark gap studs because it is very
> brittle and not a very good conductor. Metallic tungsten on the other
> hand is an excellent conductor and has a very high melting point (6000
> degrees+ F.) making it a superb choice for rotary gap studs. It works
> well for fixed gaps too.

I had a number of 1/2 inch brass rods tipped with what was supposed 
to be tungsten carbide at a local machinists shop some time ago. The 
stuff looks metallic after being faced and has no appreciable 
resistance that I can measure. The colour of the spark is a very 
bright blue. I have used such electrodes for years. They wear very 
well (slowly).