[TCML] Making a psuedo Richard Quick blown gap, ignore if not interested

["Jim Mora" <wavetuner@xxxxxxxxx>]

Hi Dennis,

Read this completely before doing anything. Richard Quick thought it was the
very best Neon gap and so did I after making one! The dowel parts are like
his.

Making a dowel gap is fairly easy. Cut (2) 1.5"- 2" long 1" diameter brass
dowels very straight faced (EBay remnants). A machinist may do this for free
if you tell him what you are making (it's a couple of minutes on a lathe)
than you have very straight faces that can be polished with #400-600 emery
paper or equivalent sand paper (a machinist is bound to have remnants too).

You need a drill press to do the next step: drill to proper size to allow
tapping a very straight hole in the center of both ends for a 3/4 long" - 1"
deep thread to except a 3/8" NC brass all thread. It may be best to just get
the machinist to drill and tap the holes while it's on the lathe and pay
him. I did it the hard way (not recommended). (BTW you want a snug fit for
the dowels that can be turned by hand)

I mentioned 3/8 brass all thread, Ace and most hardware stores carry it. I
think it comes in 12" lengths and longer. Also buy a length of right angle
aluminum or plated steel. 

Next you need to make carrier tower for the dowels. I prefer they be
vertical for equal heating at the gap. Here's how I made mine: I found a
couple of sizes of clean disposal microwave dinner dishes (sized Tupperware
would work better) and some fiber glass. You want to make the supporting
towers very perpendicular in both directions. A level or a square on blocks
if you have a level surface should work well. If the tower is 1" angle
aluminum or iron Make sure the flat face faces inward and the angled piece
is straight out. Any very rigid material will work, I used extra the dowels
I had. They should be about 6-8" long and ~6-8" apart. Drill a hole  through
your support stock 1" form the top to except the all thread. You will put a
brass nut on either side of the vertical stock. Cut the all-thread in half
and let the outward sides run wild. You can cut it off to size latter to
except your hookup wire lugs. 

Assemble the gap and screw the gaps out (toward the center) 3/4 of the way.
You want to be sure to have enough clearance that you will be able to screw
both gaps in and be able to remove one for easy cleaning and polishing of
both dowels (needed after 30 minutes of full on operation or so for optimum
performance). When you are sure you can do that, push the faces tightly
together (extended) and wrap some duck tape around them. Now the assembly is
ready to be set (blocks of phenolic or g10 cut to size and similar base
plate insulation would be better but will requires some searching and maybe
more $$).

While you are at Ace, buy a quart of marine epoxy where available. Pour
enough in the disposable dish and mix in the catalyst. Prop the assembly in
the epoxy and poke in some fiber glass for reinforcement and to prevent
cracking.

This stuff sets pretty fast so be sure you have the supports where you want
them. Since you assembled the gap prior to base alignment, the critical part
is already set.

After the epoxy is cured ( best leave it over night) you are ready to set
the gap.

Remove the duck tape and spread the gap out to >.125" or so dependent on
your transformer voltage. You are using the transformer only on a table or
workbench. This is a good time to adjust the Terry filter safety too if you
have one and should if it is a neon transformer(s). Set the Terry gap so
both sides just start to fire when your variac is full on. You may want a
piece of dry cardboard to fan the ions away during the adjustment steps.
Back them off slightly. 

Next connect the dowel gap. You want to back the gaps until they just start
to fire. You may want to fan the gap between adjustments. Some suggest this
be done under the hyperbaric conditions but I didn't and it works great
although in theory it is slightly over-volted in the higher air pressure.
Find a drill or shave a piece of wood for your feeler gauge to fit the
adjusted gap. Anytime you disassemble the gap, use the drill or feeler to
set it again. Simple and very precise.

Than you want to setup the hyperbaric part. Ace carries Stanley (used to)
wet/dry vacs. A search on the Inet may reveal a 12" long Stanley nozzle
accessory, here is something close:
http://www.totalvac.com/parts/906-83-00.html?zmam=6843742&zmas=1&zmac=6&zmap
=906-83-00 It has a 2.5" opening, mine proceeded down to ~ .5"- .75" for
real concentrated pressure. It was positioned at a 45 degree angle up
through the gap and was about .5" to .75" away from the gap. I was using a
high power leaf blower coupled though a 2.5" PVC pipe. The rubber sewer dual
hose clamps are very handy for connections which are available through most
hardware stores.

When you tune up the coil and crank it up, the gap will make a loud ripping
noise if all is well.

Good luck and if you have any questions contact me off list.

Great Sparks,
Jim Mora
 
-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of otmaskin5@xxxxxxx
Sent: Sunday, March 15, 2009 9:10 AM
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] JAVATC - Question

Thanks Jim.? To clarify, I was planning to use a vacuum cleaner motor - the
air output side - for a blown style gap.? 

I had considered using brass dowels like you describe.? Can you give me a
little more info on how you mounted them, adjustability, connections, etc.?
I'm trying to see if this would be within my somewhat limited machining
capability.? Thx, Dennsi


-----Original Message-----
From: Jim Mora <wavetuner@xxxxxxxxx>
To: 'Tesla Coil Mailing List' <tesla@xxxxxxxxxx>
Sent: Sat, 14 Mar 2009 11:30 pm
Subject: RE: [TCML] JAVATC - Question



Hi,
It seems to me that hyperbaric, curved gaps have some complicated
aerodynamic physics.

As the compressed air enters the gaps it will accelerate across the closer
faces increasing the pressure/velocity....

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