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Bottle Capacitors
Hello Troy & coilers:
It's nice to hear of other Canadian hams building Tesla coils!
Like yourself, I live in a small town, on Lake Huron, several
hours drive from any electronic supply houses or surplus
shops. I therefore went the salt water cap route too as
the materials are readily available.
My cap has a measured capacity of .0055 uF. and is made from six
Corona Extra 650 mL. beer bottles. They are filled with a brine
solution up to the point where the sides start to taper into the
neck. I have about a 1/4 inch of mineral oil floating on top of
the brine to help suppress corona (the non-beer variety).
For the electrodes, I used 1/4 inch threaded rod which hangs in
the bottle to within about an inch of the bottom. I used old
plastic 35 mm film containers as the tops for the bottles to
support the rods and also to act as a safety pressure vents.
All six bottles are sitting in a plastic Tupperware container
which is also filled with brine to the same level as that in
the bottles. Again, a 1/4 inch layer of mineral oil floats
on the brine. I used a sheet of galvanized metal bent into
an L shape to cover the bottom and one end of the container
as the second electrode.
The whole cap cost me less than $10, and it works just fine for
now, but I do intend to build an MMC when I can get to the city
and pick up the caps, as the bottle caps are lossy. Their glow
when in use does look neat, though. Let me know how you make
out with your coil.
73, Weazle, VE3EAR/VE3WZL
Listening: 147.030+ and 442.075+
E-mail: weazle-at-hurontel.on.ca
or ve3ear-at-rac.ca
Web site: www.hurontel.on.ca/~weazle