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Re: [TCML] Spark Gap Electrodes - Flat or Rounded

The zen that I followed when building my 15kv / 120ma was that the
critical discharge circuit must be 100% copper. I used copper plumbing
pipe because it's cheap and ubiquitous. See the pics at
https://teslafirma.shutterfly.com/

When the caps first discharge I wanted every amp possible flowing
through the primary. So there is not a single bit of tank circuit that
isn't copper. When I needed some copper washers I got some Canadian
pennies from before 1967 which are 99% copper and drilled holes in them.

I also theorized that the electromagnetic field around the primary is an
expanding and contracting torus. I wanted my caps to be as close as
possible to keep the connections short. If my caps were positioned in
concentric arcs then the primary field would cut across them and some
canceling out would occur. So I arranged my caps in radial lines. It's a
tiny thing I know but that's why some hot rods win and others come in
second.


On 01/19/16 11:39, Gary Lau wrote:
> No, unless you're using steel wire in the tank circuit.  Cabling to/from
> the Terry Filter is strictly low current and anything at all will do.  For
> a 12/30 powered coil, steel hardware won't matter at all.
> 
> Regards, Gary Lau
> MA, USA
> 
> On Tue, Jan 19, 2016 at 8:03 AM, p_novotny via Tesla <tesla@xxxxxxxxxx>
> wrote:
> 
>>
>>
>> I have quite a bit of steel in use on my 12kv 30ma coil (spark gap, terry
>> filter connectors, bucket cap connectors), would I see a considerable
>> improvement by changing those to copper?
>>
>>
>> Sent on the new Sprint Network from my Samsung Galaxy S®4
>>
>> -------- Original message --------
>> From: Gary Lau <glau1024@xxxxxxxxx>
>> Date: 01/19/2016  6:55 AM  (GMT-06:00)
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] Spark Gap Electrodes - Flat or Rounded
>>
>> 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
>>>>>
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>>>>
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