Re: From Portugal-tungsten electrodes

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Luc Benard <ludev@xxxxxxxxxxxx>

Hi Jose Luis,

Just forget the carbon arc welding rod, they are tuff but they are build to 
sustain the arc; in the center they are dope with a material (I don't 
remember witch one) but this material is a good electron emitter when 
heated, exactly the inverse of what you need for a good gap because with 
that the gap will never quench. May be you could make a good gap with 
plasma cutter electrode especially if you put them face to face and blow 
air trough there hole, but verified the kind you have, because all the 
electrode I saw for plasma cutter use a hafnium or hafnium composite ( 
carbide or nitride sometime with zirconium ) nucleus instead of tungsten 
because at high temperature in presence of air tungsten oxide to rapidly. I 
don't know how this material will behave in a gap.

English is not my natural language ether but people here seem to understand 
that ;-)

Cheers,

Luc Benard

On 10-Apr-05, at 12:43 PM, Tesla list , Fritz , )@pupman.com wrote:

> Original poster: =?iso-8859-1?Q?Jos=E9?= =?iso-8859-1?Q?_Lu=EDs?= 
> <jose-luis@xxxxxxx>
>
> Hi,
>
> First, thank you all for the worm welcome. I never thought that this list 
> was so active and had so many members. It's a good surprise.
> When I first read about tesla ciols and spark gaps. the first material I 
> thought using for it was a Tig tungsten electrode. I'm a blacksmith and 
> I've been using hem for quite a while. But I also remenbered that every 
> time I forget to open the Argon gaz, the electrode melts instantly. But I 
> don't know the results without trying, tomorrow I'm going to by some 
> thicker electrodes, mine arre just 2mm diameter.
> I also thought about using plasma cutting electrodes. they are made of 
> copper with a nucleum of tusgstem. The copper even has a thread in its 
> body so they are easily fitted. There's also carbon arc welding 
> electrodes. They arre used to make grooves and for cutting. I never worked 
> with it but I believe they withstand large currents without melting. When 
> I was in High school I used carbon electrodes from used 4,5v batteries to 
> make electric arcs using a regular AC welding machine. They didn't wear 
> out easily.
> Sorry if I took too much of your time, I should have consulted the 
> archives to see if this subject had already been treated, but I didn't get 
> the time yet and I thought the subject followed the thread of the list.
>
> Thank you all.
>
> Sorry for any mispelling but i'm not from a english talking country.
>
>
> Jose Luis