Doug
From: msweeney23@xxxxxxxxx
Sent: Thursday, January 21, 2016 2:19 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Spark Gap Electrodes - Flat or Rounded
I did have a belt sander but it got returned to HD due to being junk (it
actually broke on first use).
Since then i've been trying to find a source of affordable tools that are
also well made and reliable. My search is not going great so far :/
----- Reply message -----
From: "Phil" <pip@xxxxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Subject: [TCML] Spark Gap Electrodes - Flat or Rounded
Date: Wed, Jan 20, 2016 5:55 AM
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
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