Re: Tungsten vs. Tungsten

To: tesla-at-poodle.pupman-dot-com
Subject: Re: Tungsten vs. Tungsten
From: Benson_Barry%PAX5-at-mr.nawcad.navy.mil
Date: Sat, 30 Nov 1996 14:29:00 -0400 (EDT)

I would be interested also.
10 pieces 1/8" diameter X 3" long.
10 pieces 1/4" diameter X 3" long.
Barry

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|From: "tesla-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|To: Benson Barry; "Tesla-list-subscribers-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|Subject: Re: Tungsten vs. Tungsten
|Date: Friday, November 29, 1996 4:38PM
|
|<<File Attachment: 00000000.TXT>>
|> Subject: Re: Tungsten vs. Tungsten
|
|
|From bturner-at-apc-dot-net Fri Nov 29 12:53:59 1996
|Date: Fri, 29 Nov 1996 02:22:09 -0800
|From: open_minded <bturner-at-apc-dot-net>
|To: tesla-at-pupman-dot-com
|Subject: Re: Tungsten vs. Tungsten
|
|Tesla List wrote:
|>
|> >From richard.craven-at-mkbbs.co.uk Thu Nov 28 20:39:15 1996
|> Date: Wed, 27 Nov 96 20:11 +0000
|> From: richard.craven-at-mkbbs.co.uk
|> To: TESLA-at-pupman-dot-com
|> Subject: Re: Tungsten vs. Tungsten
|>
|> Daryl and everyone
|>
|> [Daryl said:
|>
|>    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.]
|>
|> Thanks for taking the trouble to look into the idea of using tungsten
|> carbide. As we can see, it is not an insulator, but different grades
|> have differing conductivities. A piece that I measured at work using a
|> DVM was short circuit ( it was an uncoated tooling bit about half an
|> inch long by 1/4 inch thick, lozenge shaped).
|>
|> [From Brent:
|>
|>    Used the round disks that I silver-brazed onto brass
|>    studs. In all honesty, they ablated (wore) away very quickly. I had
|>    used 3/8" round tips. I now use 3/16" pure tungsten rod, which is
|>    smaller, and ablates a bit more slowly. From what I understand, if
|>    you can cool the electrodes down a bit, they last longer. I plan to
|>    put a high-velocity blower nozzle on my gap to cool things down.]
|>
|> My intention is to use tungsten carbide rods, 5mm diameter by 10mm long,
|> inserted into my s-s electrodes. The electrodes on the disk will be
|> cooled by virtue of 3000rpm speed, and the 4 stator electrodes are sunk
|> in turn by large aluminium blocks (2 inch tall by 2 inch diameter
|> cylindrical blocks). Air could be blown at the gap channels but I hope
|> not to need to do this.
|>
|> My interest in using tungsten carbide is because it is more available
|> for me than the tig welding electrodes. I expect them to be a viable
|> alternative as long as their conductivity is checked. I am having my
|> rods made by a local company. The cost works out the same as buying
|> machine inserts. The material is usually tungsten carbide and ditungsten
|> carbide ( made by heating metallic tungsten with a small amount of
|> cobalt as a catalyst) which is sintered at a low temp (900 deg C) and
|> then machined. It is then high temperature sintered (1300 deg C) at
|> pressures of several tens of kg per mm sq. Cobalt  is added here as well
|> to help with the sintering. Co dissolves 30 or 40 per cent by weight of
|> W and thus helps the mixing and sintering process. Other matls can be
|> added (ceramic fillers) which will account for differing conductivities.
|> I will be using the rods end on probably. If I go for disks or other
|> shapes, edgeways on as RWS suggests is an excellent idea.
|>
|> Richard Craven, Malvern, England
|> ---
|>  CMPQwk #1.42 UNREGISTERED EVALUATION COPY
|
|
|Richard -
|
|  What kind of costs are you looking at for the Tung-carb rods? I'd be
|tempted to try a couple in my gap to see what happens.
|
|- brent
|