That opens another question.. in this case is it better to have a smaller (more aggressive) radius for the rounding (e.g. an acorn nut vs. a 3/4 inch spherical brass electrode)?
For the simple linear spark gap it seems smaller is better but the RQ types use copper tubes which are much larger diameter.
It seems to me the smaller radius would allow for faster quenching.
Matt
----- Reply message -----
From: "Gary Lau" <glau1024@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: [TCML] Spark Gap Electrodes - Flat or Rounded
Date: Tue, Jan 19, 2016 6:55 AM
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
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
>>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
>> _______________________________________________
>> Tesla mailing list
>> Tesla@xxxxxxxxxx
>> http://www.pupman.com/mailman/listinfo/tesla
>>
>>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla