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Where do I get Tungsten welding electrodes?
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From: D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Saturday, March 21, 1998 8:44 PM
To: Tesla List
Subject: Re: Where do I get Tungsten welding electrodes?
to: Ed
The photos are enroute.
DR.RESONANCE-at-next-wave-dot-net
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> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: Where do I get Tungsten welding electrodes?
> Date: Friday, March 20, 1998 10:33 PM
>
>
> ----------
> From: Edward J. Wingate [SMTP:ewing7-at-frontiernet-dot-net]
> Sent: Friday, March 20, 1998 5:36 PM
> To: Tesla List
> Subject: Re: Where do I get Tungsten welding electrodes?
>
> Tesla List wrote:
> >
> > ----------
> > From: Mark S. Rzeszotarski, Ph.D. [SMTP:msr7-at-po.cwru.edu]
> > Sent: Wednesday, March 18, 1998 4:55 AM
> > To: Tesla List
> > Subject: Re: Where do I get Tungsten welding electrodes?
> >
> > Hello All:
> > Cliff said in part:
> > >I noticed that you mentioned that .38 in tungsten tip rods would be
good
> > >to use on the stationary part of a rotary gap. Is there any reason
that
> > >they can't be used on the rotating part of the RSG?
> > I have not built a rotary yet but have studied their design.
They
> > are EXTREMELY DANGEROUS devices, especially if you spin them up over
5000
> > RPM which some folks do. The centrifigal forces make them a lethal
weapon.
> > Perhaps one of the experienced rotary folks can step in here and
discuss
> > design a bit. A couple of folks on list are experienced machinists who
have
> > built real masterpieces and understand the need for safety. (Ed, Dave,
> > Richard, Bill, Greg, D.C., others step forward at this time.)
> > Regards,
> > Mark S. Rzeszotarski, Ph.D.
>
> Cliff, Mark,all,
>
> I used the tungsten tipped steel rods sold at welding supply stores to
> build a rotor for a rotary gap for a friend. The only reason being that
> that's what he wanted me to use! There is a drawback using these as
> opposed to the solid tungsten studs that I prefer to use. Since they
> only have tungsten on one end, they must be connected together
> electrically on a G-10 rotor and the stationary studs must both/all be
> mounted on the same side of the rotor. This means each stud must be
> carefully drilled and tapped to accept a machine screw to enable
> fastening copper straps to the rear side of the rotor studs to
> electrically connect each to the next around the whole circumference of
> the rotor. Each strap must be the same size physically to keep the
> weight the same and the tapped holes in the studs must be drilled and
> tapped to the same depth for the same reason to make final balancing of
> the wheel less difficult. And balancing is a must for any high speed
> rotor. You can use an aluminum rotor to avoid having to physically
> connect all the studs together, but this presents the problem of needing
> to electrically isolate the rotor from the drive motor. There is also
> the possiblity of the tungsten ends flying off the holders if the gap is
> overheated sufficiently to melt the braze that connects them to the
> steel holder. I have had these buttons FALL off a stationary gap that
> was overheated. A good heavy guard should prevent any personal injuries
> or fatalities should this happen, no rotary gap should be without one!
> And under NO circumstances let anyone stand in line with the rotor of an
> operating rotary gap! Almost nothing will ruin your afternoon more
> quickly than someone getting seriously injured or killed by a supersonic
> piece of tungsten!! This is supposed to be a fun hobby, not a deadly
> one!
> As I have stated before on this list, I regularly spin the G-10 rotor on
> the series-rotary gap on my magnifier system to 7500-8000 RPM, verified
> by an infrared strobe tach, with no problems. The rotor on this gap is
> 1/2" G-10, 11" in diameter, uses 6- .250 diameter solid tungsten studs
> and will handle 10 KW easily as attested to by solid 4 minute run times.
> I can supply solid tungsten studs in sizes up to 1/2".
>
> I hope this info helps a bit.
>
> Safe coiling,
>
> Ed Wingate
>
>