Just beware that many cap nuts sold (I'm looking at you Home Depot) are
just brass-plated white metal.
Regards, Gary Lau
MA, USA
On Mon, Jan 18, 2016 at 11:18 PM, Carl Noggle <cn8@xxxxxxx> wrote:
> Brass cap nuts (acorn nuts) from Ace Hardware make excellent electrodes.
> Maxwell used brass electrodes in their big Marx gaps used for 30,000 amps
> and they had very long life.
>
> You can also get copper-tungsten rods, which machine very well, about 15%
> Cu and 85% W. I've been using the same set for 20 years in my 2 kW coil
> with occasional polishing.
>
> ---Carl
>
>
>
>
>
> On 1/18/2016 5:26 PM, msweeney23@xxxxxxxxx wrote:
>
>> 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
>>> _______________________________________________
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>>> Tesla@xxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
>>> _______________________________________________
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>> Tesla mailing list
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>>
>>
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