Re: Tungsten vs. Tungsten Carbide

To: tesla-at-pupman-dot-com
Subject: Re: Tungsten vs. Tungsten Carbide
From: Richard Hull <hullr-at-whitlock-dot-com>
Date: Sat, 18 Mar 2000 21:59:08 -0800
Tesla List wrote:
> 
> >From mycrump-at-concentric-dot-netSat Nov 23 20:07:58 1996
> Date: Sat, 23 Nov 1996 20:10:01 -0500 (EST)
> From: "Daryl P. Dacko" <mycrump-at-concentric-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Tungsten vs. Tungsten Carbide
> 
> I spent several hours today playing around with my arc lamp
> power supply and some tungsten rod and a tungsten carbide lathe
> insert to see which faired better in a torture test.
> 
> Snip

> The tungsten rod burned back about 3 to 4 times as fast as the
> carbide insert and left a pretty yellow deposit of tungsten oxide
> crystals around the rod.
> 
> The carbide insert burned back only 1/8 of an inch and left very
> little deposit on the tip.
> 
> By careful guesstimation, and use of my DVM, I'd say that I'd have
> about three ohms more resistance in each tip useing a carbide tip
> than using tungsten rod, which might work out to only losseing
> five watts or so more than using rod.
> 
> I think I could build an effective holder for these tips by slotting
> an alunimum bar and drilling a thru hole to fit the 3/16" hole in
> the tip.
> 
> These carbide tips look better all the time !
> 
> Has anyone else tryed carbide tips in a rotary ?
> 
> Daryl


Daryl,

Three ohms is atrocious!  If that is indeed the case, then it is "loss 
city for the carbides."  assuming two 3 ohm rods, you have placed 6 ohms 
in the tank discharge circuit.  With about 100 amps flowing in a normal 
1KW-2KW coil's tank, with 20KV peak voltage, that would mean a rod loss 
(no even counting arc losses), of about 60,000 watts of peak energy!  The 
average gap loss would normally be about 20-30KW peak.  The difference 
might not make much difference in the visual aspect of coiling though.  
Still, I'll stick with my thoriated tungsten.

Richard Hull, TCBOR