Two brass cap nuts (acorn nuts) with the domes facing each other work well,
and it's easy to adjust. 3/8 is a good size. It's good not to have sharp
corners or edges where the spark can jump form them. You will need a blower
blowing across the gap. You can adjust the amount of air flow by finding a
flow rate above which there is no further increase in performance, then go
50% higher. If you put the gap electrodes on each side of a piece of clear
plastic pipe, you can direct the air through the pipe and put some sort of
muffler on it if you like.
---Carl
-----Original Message-----
From: Jim Lux
Sent: Friday, February 07, 2014 8:21 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Tesla coil- spark gap
On 2/7/14 5:46 AM, matty mcqueeney wrote:
Could anybody help me find a reasonable spark gap, that is simple to make?
Thanks Matthew.
simple static gap?
I like using three pieces of copper pipe parallel to each other..
http://home.earthlink.net/~jimlux/hv/tesla.htm
has a drawing and pictures..
It's easy to adjust (move the center pipe relative to the two fixed
pipes), has a lot of surface area (important so you don't get a hot
spot), and performs well with a small fan blowing along the axis of the
pipe.
If you're running more power (say >1 kW) then you might want to try some
other designs. multi gaps are popular, but have higher loss. Rotaries
work well, but are mechanically complex. A single blast gap can work
well, but you need an appropriate source of air (blower or compressor,
depending on the design)
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