Sent: Tuesday, January 19, 2016 7:55 AM
To: Tesla Coil Mailing List
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
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