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COILBLD3.TXT


Text file for COILBLD3.GIF, graphical instructions for 
construction of high performance 1/4 wave Tesla resonators. 

This series of diagrams shows details of the coil base and the
steps required to construct a high current ground terminal
without drilling into the coil form or permanently mounting
protruding hardware.

7) The first step in constructing a high current ground terminal
is to cut out a rectangle in the sealer at the base of the coil
form just below the winding. The coil winding should end just
above one corner of scribed area. The cut should be about two
inches long and one inch high, minimum. This section of sealer 
is then peeled and scraped away to expose the bare plastic coil
form. Use a blade and deeply score and cut the bared plastic in 
a "cross-hatch" pattern.

8) Cut a strip of copper from some heavy copper sheet. The strip
of copper should fit inside of, and almost fill, the cleared and
scored area on the coil base. Round the corners of the copper
strip, then bend the strip gently until it conforms exactly to
the curvature of the coil form. The rounded and curved strip of
copper should fit neatly on the coil form in the prepared area.
If copper sheet is not available the ground terminal may be
constructed by splitting open a section of copper water pipe and
peening out the proper shaped terminal. 

9) This next step requires a piece of steel (with a flat surface)
and a small hammer. Gently pull the base wire of the coil free
from the sealer. Pull the wire up all the way to the beginning of
the winding. Once freed, trim this wire, leaving a 2-1/2 inch
length. Scrap the base wire clean of all sealer and enamel
insulation. 

Next, carefully wrap some heavy plastic or cardboard around the
coil to protect the winding from dings, but leave the base wire
extended and exposed. Position the coil so that the base wire may
be laid out flat on a small steel block or plate, then gently
peen the wire out with a small hammer. Copper wire is very
malleable, it will be possible to peen the round wire into a thin
flat strip. Trim the length again if required.

10) Clean and tin the inside curved surface of the copper strip.
Clean and tin the peened out base wire from the coil. Using a
clothes-pin, or other small clamp, position the flattened base
wire diagonally across the inside curve of the copper strip.
Solder the two together with a very hot iron. Avoid clumps or
blobs of excess solder. Clean the soldered area thoroughly with
solvent to remove all traces of rosin, oil, and dirt. Sand the
soldered area gently with abrasive paper to smooth out any rough
areas and high spots. Clean the soldered area a second time.

11) Using a cloth or lint-free wipe, clean the scored rectangle
on the coil form base with solvent, carefully removing all traces
of oil and dirt. Wipe down the copper ground terminal one last
time. Prepare some strips of waxed paper and an assortment of
rubber bands. Mix up a small batch of clear, two-part epoxy.
Smear the scored rectangle on the coil form with epoxy, then
smear the inside curve of the copper ground terminal. Fit the
ground terminal into place, cover with strips of wax paper, and
secure with a couple of rubber bands around the coil form. Allow
sufficient time for the epoxy to gel firmly, but do not allow a
complete cure. Remove the rubber bands and the wax paper strips. 
Gently scrape away excess epoxy from the surface of copper ground
terminal, then wipe the terminal surface clean with solvent. 

If attention has been paid to detail and technique, the copper
ground plate should be nearly flush and firmly attached to the 
bottom of the coil form just below the winding. Sometimes it may
be necessary to fill in a low spot or two with a second tiny
batch of epoxy.

12) This figure shows how effective this ground terminal is in
practice. It is quite easy to connect one inch SMOOTH grounding
strap directly to the base of the coil with a couple of rubber
bands or a long strip of electrical tape. This connection is
ideal for removing the heavy RF current produced at the base of
the coil. This ground terminal is also nice in that it may be
quickly connected and disconnected, offering flexibility and ease
of setup. This system is also efficient if the base terminal is
to be used to feed RF current into the bottom of the coil, as in
the extra coil of the Tesla Magnifier. 

Being flush mounted without drilling holes into the coil form,
this terminal preserves the electrical strength of a sealed coil
form. Without protuberances typical of other terminal types,
there is nothing to break off or damage. The same lack of pro-
tuberances makes it easy to store several coils close together
without worry of scratching or cutting the finishes. This
terminal is clean and professional looking.


COILBLD3.TXT     11/26/95          Graphics and text prepared by:

Richard T. Quick II                <richard.quick-at-slug-dot-org>
10028 Manchester Rd 
Suite 253
Glendale  MO  63122  USA