Stefan
Yes, without doubt they ablate quicker than the 1/4 inch Tungsten (doped
ones) that they replaced. In theroy going up from 1/4 to 3/8 should have
meant less ablation anyway on account of the size change alone! I can't
remember with certainty what the original (replaced) 1/4 inch Tungsten ones
were doped with though, but I think that disc used Zirconiated ones.
Obviously I'm talking about ablation on the fixed ones, as in any setup the
flying or revolving pair rarely seem to ablate.
I can't recall the % values of Cu to W of the ones I'm using, but I can find
out from my colleague.
Are they worth the expense (?) - well not really sure, as 3/8 inch Tungsten
welding rods are not available in the UK, so it means you would have to
import pure Tungsten slugs anyway if I had chosen that route.
Regards
Phil Tuck
www.hvtesla.com
-----Original Message-----
From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Teslalabor
Sent: 20 January 2016 13:10
To: Tesla Coil Mailing List
Subject: Re: [TCML] Spark Gap Electrodes - Flat or Rounded
Hi Phil,
I'm actually upgrading my rotary and thinking about the correct electrode
material. I also thought about using tungsten/copper (80% tungsten 20%
copper) where the manufacturer says, it is way more stable (ablates much
slower than pure tungsten). But you say, it ablates quicker, than pure
tungsten? I'm a little bit confused now... Also thermal and electric
conductivity is much better with tungsten/copper, also it is lighter... So
why use pure tungsten?
Regards,
Stefan
----- Original Message -----
From: "Phil" <pip@xxxxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Sent: Wednesday, January 20, 2016 12:55 PM
Subject: Re: [TCML] Spark Gap Electrodes - Flat or Rounded
> Matthew,
> You can round out the ends of Tungsten (in my case 0.25") by a belt sander
> or linisher, and using a drill.
> It WILL wreck the belt though, but I find I can do eight ends on an
> already
> used belt ok.
> Start the belt and chuck the Tungsten in the drill and simply hold against
> revolving belt. I used to make half hemispheres but now I find just
> rounding
> the edges is sufficient - just need to lose the 90 degree edge.
>
> You can just make the curve out in third photo down:
> http://www.hvtesla.com/srsg_2015.html (statics are 3/8 Tung / Copper,
> revolving are pure Tungsten)
>
> Green welding rods (pure) are harder to do than those that are doped with
> something, I have found though.
>
> Tungsten copper will cut very easily and you can round those with a file,
> but it ablates quicker (3/8 inch Diam' on 7kw or so)
>
>
> Phil
>
>
>
>
>
>
> -----Original Message-----
> From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of
> msweeney23@xxxxxxxxx
> Sent: 19 January 2016 00:26
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Spark Gap Electrodes - Flat or Rounded
>
> Ok thanks, maybe ill just use screw on brass electrodes for now i dont
> have
> anything to round out tungsten.
>
> Sent from my HTC
>
> ----- Reply message -----
> From: "Carl Noggle" <cn8@xxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Subject: [TCML] Spark Gap Electrodes - Flat or Rounded
> Date: Mon, Jan 18, 2016 6:12 PM
>
> All spark gaps should be rounded. The field enhancement at the edges of
> a flat gap electrode will cause it to go into corona before the spark
> forms, giving erratic operation. A radius of curvature less than about
> 25% of the gap spacing will go into corona first. Also, with wear the
> electrodes will eventually become rounded, requiring adjustment during
> the process. (Nature usually knows best.)
>
> ---Carl
>
>
>
>
> On 1/18/2016 4:21 PM, Matthew Sweeney wrote:
>> I see a great deal of conflicting information regarding this, and I'm in
>> the process of making my tungsten spark gap for a small single NST
>> (12k/30ma) coil.
>>
>> Should I be using tungsten rods with flat ends, or rounded? I've heard
> that
>> rounded ends are good for safety gaps but actual spark gaps should have
>> nice flattened ends. Is this true for static gaps and not just rotary
> gaps?
>>
>> I will eventually make an RQ gap but starting off simple for now with a
>> basic one or two static rod gap design.
>>
>> Any help appreciated!
>>
>> Matt
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
>>
>
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