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Scot's spark gap in progress

Subj:    Re: Scot's spark gap in progress
Date:   2/26/00 9:55:22 AM Central Standard Time
From:   tesla-at-pupman-dot-com (Tesla List)
To: tesla-at-pupman-dot-com

Original Poster: "Samuel Rosset" <samr-at-bluewin.ch> 

Hi Ralph, Scot, All

I am also building a Scot Gap, so here are my comments, and my question

>>>With perfectly parallel ditches, you can hold your tubes with only one
screw, and you are sure they will be parallel. Of course the other
possibility is to drill two holes in the pipes and in the G-10. But if you
make a little mistake with the holes on the tubes, and another mistake while
drilling the G-10, those two mistakes will be added, and your tubes won't be
perfectly parallel. But with one single screw and a ditch, I think you can't
go wrong...<<<

Hi Sam, Scot, all,
Well, it looks like Scot's elegant design has growing pains. I gotta keep 
things simple.  :-))
A single 8-32 screw will hold the 1.5-inch cylinders solidly in place. True, 
you can twist them loose if you try, but the single screw holds them solid 
and the single screw allows the use of a gauge to set them parallel. A drill 
makes a good gauge but 
other things can be used. Also, now there is another factor steering me away 
from milling the ditches, and that is the factor of heat dissipation. I don't 
know what the heat capacity of G-10
might be. Especially since there are many things called G-10 and determining 
the specific heat constant for this particular G-10 could only be a guess. 
Nor do I know what temperature rise of the copper to expect. But if heat 
dissipation
is going to be a consideration, removing G-10 mass where the cylinders are 
attached is something that might best be avoided.  I have everything laid out 
now with masking tape on the G-10. I'll drill both pieces at once and start 
with a # 4 drill. Please comment.  

>>>Now, allow me to ask you a question about forced air into the gap. Can you
two tell me how you did?<<<

I have been using a Sears shop vacuum / blower and clamping the outlet nozzle 
close to the gaps I am using now. I think it makes a big difference in 
performance but I wonder if anyone can explain if 
it is possible to measure the change. The Sears is one of the vacs with the 
detachable top that's
supposed to be blowing a 200 mph tornado. There are attachment nozzles that 
will easily cover the 
width of the five cylinders.

>>> Of course, all the other faces of the gap are closed with
plexi sheets (that's what I used) to force the air to go between each gap
and escape at the top...
Does it seem to be a good idea?<<<

Not to me. Keep it simple.  :-)) Why block the circulation of ambient air? 
Also, Plexiglas runs like
taffy with just a little heat.

My plan is to clamp and bolt together the two pieces of 4 x 12 G-10 before I 
drill the holes. First, I'll drill the four corner holes for 1/4 x 20 
threaded brass rod. Might even drill two more holes at the six-inch
midline. Then I will remove the clamps and bolt the two 4 x 12 pieces 
together before drilling the nine
holes for the cylinders. Comments are cheerfully solicited.  :-((

This is great fun. Learning is happening.

Cheers,
Ralph Zekelman