-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
Behalf Of jimlux
Sent: Sunday, February 21, 2010 10:57 AM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Spark gap for first TC
John Byström wrote:
jimlux wrote:
Almost anything will "work".
I like a gap made of three pieces of 3/4" or 1" diameter copper
pipe
about 2" long arranged with the long axes parallel. So you
effectively
have 2 long skinny gaps in series. You have a small fan blow air
through the pipes (along the axis of the pipe. If you arrange
them in a
sort of squashed triangle, you can permanently mount the two end
ones,
and adjustments only need to move the middle one.
The other easy gap that works fairly well is a couple of copper
pipe
caps facing each other, with a shop vac blowing between them.
You could even do the two bolts thing, but I've found that the
bolt is
so small (even if you use carriage bolts and the gap is the head
of the
bolt) the spark always goes from exactly the same spot on the
electrode
and you get a hotspot. Once you get that glowing hot spot, the gap
characteristics change (it breaks down more easily), and the
output of
your coil drops.
The first gap you mention, when I use the long side of the copper
tubes facing each other, how do you mean it would be (like a
squashed
triangle)?
I'm probably going to start with the "two bolt thing" because of the
time limit. If I have time left, I'll try another spark gap, like
the one
you mentioned or the classic RQSG (I believe it's called)
Imagine stacking three logs in a triangle.
O
O O
If you put the lower two tubes, say, 3/4" inch apart (actual gap, not
center to center), then the upper tube can be used to adjust the gap
width (you actually have two gaps in series).
The small fan blows down the length of the tube (both inside and
outside) so the cooling is really effective.
YOu can also turn this on end and have the axes of the tubes
vertical,
which opens up some alternate mounting techniques.
The RQ gap is similar.. but not so easily adjustable. If you want to
get into multiple gaps, then one of the "laid out flat" multiple
gaps is
probably better. They're a whole row of tubes parallel to each other
with a small fixed gap between tubes. The gap is adjusted by chosing
"how many gaps".