Date: Wed, 02 Aug 95 14:53:00 EDT
From: "Lima, David" 
To: "''" 
Subject: FW: Plans for TC caps


PLANS FOR BOTTLE CAPACITOR



Go drink a sixpack of wine coolers. When your buzz wears off wash and   
clean the bottles out. Scrub off the labels.
 Discard the pop-tops and get six screw on white plastic caps from   
2-litre Schweppes bottles.
 Create a supersaturated solution of Morton salt and water. My solution   
was 8 tablespoons salt to 6 cups of water. Pour the solution into the   
bottles filling up to the level where the bottle is no longer   
cylindrical.
 For the remaining airspace, top off the bottles with 10W30 motor oil   
which will float above the salt solution.
 Drill a 1/4 inch hole in the center of each plastic screw cap. Take six   
1/4" by 8" long zinc coated carrage bolts, the kind with threads running   
only about an inch at the end (these are common). Screw  a hex nut onto   
each bolt as far as it will go.  Insert each bolt thread first through   
the bottom of each plastic cap through the hole you made  so that the cap   
rests on the nut. Screw another nut onto each bolt down over each plastic   
cap. There should be about 1/2" of thread left free.
 Take these six assemblies and screw one onto each bottle so the head of   
the bolt sticks down through the oil into the brine. Fit should be tight   
but seal the cap with RTV anyway.
 Now wrap the the cylindrical portion of the outside of each bottle with   
Aluminum foil allowing the foil the cover the bottom of the bottle. Wrap   
over this tightly with electrical tape (at least two layers). Dont wrap   
over the neck of the bottle or the foil on the underside.
 Construct a box of 3/4" pine or plywood just big enough to house the six   
pack and about 6" deep. Paint it flat black and varnish it or use some   
other insulating coating. Cover the bottom with a sheet of plate glass   
and place a sheet of Aluminum,copper,or foil on the glass.
Place the bottles in the box. The metal/foil on the glass on the box   
bottom will contact the foil  on the bottle bottoms forming one terminal   
of the capactitor.
A hole should be drilled through the box near the bottom to bring out the   
lead away from the top end. Electrically tie the bolt ends (top) of each   
bottle together with small pieces of heavy gage wire and ring lugs. That   
is the other terminal.

The beauty of this is the convenience of bottle capacitors yet everything
is dry outside. Tuning is as easy as pulling a bottle out or putting
another in. 

>From my notebook (1990):

The 'six pack' capacitor is finished and is very satisfactory. I took   
some readings of my various capacitors and got unexpected results. My oil   
capacitor is 4.8 nF according to the meter. The 'sixpack' is 4.3 nF. The   
closeness is amazing considering the advantages of the sixpack over the   
bulky oily mess with 9 1/4" plates of glass and 4 qts. of motor oil....   
each individual bottle in the sixpack read very close to .74 nF which   
suprised me....I wasn't expecting anything so uniform.

Parts List:      (for 1 'sixpack')

6 beer or wine cooler bottles (must have some cylindrical surface area)
6 plastic caps from 2 litre Schweppes bottles
1 quart 10W-30 motor oil
1 box Morton salt
3/4"x6" pine wood
1/4" window glass
1 handfull of ring lugs (for 18AWG or bigger)
Some 18AWG wire or bigger
1 box aluminum foil
6 1/4"x 8" zinc coated carrage  bolts (with nuts and stars)
2 rolls electrical tape

Notes:
Several boxes may be needed wired in parallel.
Each box (in my case) was about 4.3nF.
You can experiment with other solutions instead of salt water.
You can try bigger bottles.
I used un-iodized salt. Iodized salt contains potassium iodide and   
dextrose which may or may not give the caps more capacitance
Tesla used a similar caps in Colorado Springs.
I made a special box for tuning with the capacitance value of each   
successive bottle halved (by removing foil/tape with an Xacto knife)
I've never had a bottle explode (the deep box will shield you)

I ask that you keep me informed of any improvments or success.

Dave