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Cap info, repost



                                  April 8, 1994

                                   CAPACITR.ASC

                High voltage capacitor construction, by Bert Pool.

          First of all important warnings and disclaimers:

          High voltage  capacitors  are  very dangerous for several obvious
          and some not-so-obvious reasons.   Most experimenters know that a
          capacitor can retain a significant voltage even  after power has
          been removed.

          Discharge all  capacitors  with  a jumper cable before working on
          them.  When  discharging large  capacitors,  the  jumper  cable
          needs a high wattage 100 ohm resistor to limit discharge current.

          EVERY CAPACITOR  IN  A  "SERIES"  DESIGN TESLA  CIRCUIT  MUST  BE
          DISCHARGED SEPARATELY!  SHORTING ONE CAPACITOR WILL NOT DISCHARGE
          OTHER CAPACITORS IN THE CIRCUIT!

          Voltages and  currents  available  on  charged  capacitors can be
          lethal.  Use common sense.  The  capacitors  described  here  are
          sealed and  contain  mineral  oil.   While  mineral  oil  is  not
          especially flammable, a catastrophic capacitor failure can result
          in pressure  buildup and explosion if construction technique does
          not allow for release of pressure.

          Mineral oil will burn - a catastrophic capacitor failure can also
          result in the release of oil which  could  ignite.   It is highly
          suggested that  experimenters  keep  on hand a fire  extinguisher
          rated for oil fires.

          Also, it is suggested that oil filled capacitor banks be stood in
          a metal pan large enough to contain the oil in case a capacitor
          container is breached or oil is released.  This pan can prevent a
          mess, as well as help contain a potentially nasty fire!

          I have built over a dozen oil filled high voltage capacitors, and
          I have  had  several  failures  due  to construction shortcuts or
          material failures  and  I  have  NEVER  experienced  a  dangerous
          buildup of pressure or a fire - but I know it  CAN  happen  and I
          take measures  to be prepared for such an eventuality.  Many high
          power Tesla coils use "power pole" transformers; these too are
          filled with  oil  and  the  same  precautions  for  prevention of
          explosion and fire apply here too.

          As a high voltage experimenter,  you take full responsibility for
          safe construction and operation of your capacitors and other high
          voltage devices.

                      Be safe, be careful, use common sense!
       --------------------------------------------------------------------
       Keeping all these safety ideas in mind, presented  is  a  method for
       building home-brew polyethylene capacitors which serve very well for
       Tesla coils, ZPE devices, etc.

       The original design is not mine, it was conceived by Richard Hull of
       the Tesla Coil Builders of Richmond (TCBOR).  TCBOR has an excellent
       video showing step-by-step construction of this type of capacitor.

       Other available video tapes provide excellent info on Tesla coil and
       Tesla magnifier construction.   Richard  Hull  may  be contacted at:
                                      TCBOR,
                                7103 Hermitage Rd,
                                Richmond VA 23228.

       CAPACITOR FUNDAMENTALS:

          A simple capacitor consists of two conductive plates separated by
          an insulator.  Capacitance  is  determined by  the  area  of  the
          plates, the  distance  between them and the "dielectric constant"
          of the insulator between the conducting plates.

          This dielectric constant is represented  by  a number called "K".
          On the next page is a table of materials and their  "K" and their
          puncture voltages taken from the "Radio Amateurs Handbook":


               MATERIAL               |   "K"          |  PUNCTURE
                                      |                |  VOLTAGE PER
                                      |                |  MIL
                                      |                |
       =============================================================
               AIR                        1.0             240
               BAKELITE                   4.4 - 5.4       300
               BAKELITE, MICA FILLED      4.7             325 - 375
               FORMICA                    4.6 - 4.9       450
               WINDOW GLASS               7.6 - 8         200 - 250
               PYREX GLASS                4.8             335
               MICA                       5.4             3800 - 5600
               PLEXIGLASS                 2.8             990
               POLYETHYLENE               2.3             1200
               POLYSTYRENE                2.6             500 - 700
               PORCELAIN                  5.1 - 5.9       40 - 100
               QUARTZ                     3.8             1000
               TEFLON                     2.1             1000 - 2000


       A vacuum or  air  has  a  "K"  of  1.   If you put a piece of teflon
       between your plates (same spacing),  the  capacitance  will increase
       2.1 times and it will handle at least 5 to 7 times as much voltage.

       If you used  a  piece  of good quality glass, the capacitance  might
       increase 8 times! (the voltage rating would increase only slightly).

       The dielectric you  choose  will be determined by voltage, frequency
       (if using a.c.), durability (glass  breaks  very  easily),  cost and
       physical size.

       MATERIALS AND SOURCES:

       The capacitors we will build use polyethylene.  Poly is very easy to
       work with, does  not break, is inexpensive, readily  available,  has
       very good a.c.  characteristics  (very  low loss), and has good high
       voltage properties.  Mica would  be  even  better,  but  it  is VERY
       expensive and is not readily available.

       Glass is o.k. as far as availability and cost goes,  but it has very
       high internal losses for Tesla coil use, compared to poly.  Glass is
       also very fragile to work with.  I've made glass capacitors weighing
       over 600 pounds -NEVER AGAIN!  You just can't beat making capacitors
       out of polyethylene.

       Purchase two sheets  of  polyethylene  sheet,  48  inches wide by 96
       inches long.  Each sheet will be cut  lengthwise  into three sheets,
       each 16 inches wide.  All together, you will have 6  pieces  of poly
       16 inches wide  by  96 inches long.  This is enough material to make
       THREE capacitors. (You will cut several more sheets if you choose to
       use several thin layers of plastic instead of one single thick
       layer.)

       The thickness of the poly sheets  is  determined  by the voltage you
       will be placing  on  the capacitor.  You have to take  into  account
       whether you are using d.c. or a.c.

       If you are  using  d.c.  voltage,  calculate  your poly thickness by
       using dielectric voltage rating of 600 volts per mil (one mil = .001
       inch).  Some charts show that poly can handle 1200 volts per mil -
       Tesla coil experience  shows  that  this  value  is NOT conservative
       enough, even taking peak-to-peak values into account!

       If you are using a.c., and especially with a Tesla coil, you have to
       de-rate the voltage ratings on the  poly  or you will have capacitor
       failure.  For Tesla coils using input transformers  from 9 kilovolts
       up to 15  kilovolts,  use  90 mil thick polyethylene.  If your input
       transformer is 7200 volts or less, you can use 60 mil poly.

       *** Special construction note!  Once you have determined the
       required capacitor dielectric thickness, it is MUCH better to make
       your dielectric from several thin sheets of poly instead of one
       single thick sheet.  Example:  If you need 90 mil thick poly, use
       three 30 mil pieces stacked together to form a 90 mil dielectric. If
       you use multiple layers the insulation will be MUCH more robust than
       a single thick layer.  The reason?  If you were to use a single
       thick layer of poly and it had a manufacturing defect, odds are that
       the defect will extend all the way through the plastic.  High
       voltage would force its way through the single defect to blow up
       your capacitor.  If you have three or four thin layers stacked,
       every sheet might conceivably have a defect,  BUT it would be almost
       impossible for all of the defects to be lined up to allow the high
       voltage to punch through.  Odds would be that while one sheet might
       have a defect, you would still have several GOOD layers still
       providing protection.  Professionally manufactured capacitors
       usually use this secret of layering.

       *** From this point on, where the text describes using "a" piece of
       poly, you will probably instead be substituting three or even four
       thin sheets of poly for the reason described above.  Keep this in
       mind during the construction process!


       The capacitor described, using .0625  inch  thick  polyethylene will
       have a measured value of 0.0185 ufd with an a.c. working  rating  of
       7500 volts r.m.s.***    A   .090  inch  thick  polyethylene  dielectric
       capacitor will have a value closer  to 0.010 ufd, and can be used in
       Tesla coil circuits using a power source up to 15 kilovolts a.c.

                 *** TCBOR suggests that .060 thick poly will work -at- 15,000
                 volts.  My experience shows this is not always true.  I
                 recommend 90 mil poly for 12,000 to 15,000 volt operation.


       As any coil builder knows, the resonant peak voltages  go  WAY above
       the source voltages!   You must design sufficiently thick poly
       dielectric to handle this higher voltage.

       Power  LOSS  in  one of these caps in a Tesla coil configuration is
       LESS than 0.5  watt per cap!  Thus, they don't suffer from internal
       r.f. losses which translate into heat failure.

       A poly capacitor made with .060 poly should handle 36,000 volts d.c.
       and the .090 thick poly job should easily handle 54,000  volts  d.c.
       These are very  conservative  ratings  -  good  quality polyethylene
       might handle twice these ratings.  Tesla coils, of course, use
       alternating current.  The peak voltages generated in a resonant
       Tesla circuit are incredibly hard on a capacitor.  This is why you
       must "over-engineer" the voltage capabilities of your capacitors.

       Capacitors may be  placed  in series  to achieve  higher  voltage
       ratings, parallel for more capacitance.  Combination series/parallel
       combinations may be used to achieve any desired capacitance and
       voltage rating.

       As an example, let's say you've built several 0.01 ufd capacitors
       rated at 7,500 volts.  You make the deal of your life and acquire a
       terrific 15,000 volt power transformer....only your capacitors can't
       handle this voltage.  What to do?   Assuming your coil requires a
       capacitance of 0.01 ufd, what kind of connections can you make to use
       the capacitors on hand?

       First of all, you could connect two caps in series, as shown below:


                c1          c2            0.005 ufd 15 kv capacitor
                ||          ||            made from two 0.01 ufd, 7.5 kv
       ---------||----------||------      capacitors
                ||          ||


       You now have a capacitor rated at 15,000 volts...BUT the capacitance
       is now only .005 ufd!  You increased the voltage rating, but placing
       capacitors in series reduces the capacitance.  Now what?  We connect
       two more caps in series to create another 0.005 ufd capacitor, then
       we take our two 0.005 ufd caps and put them in PARALLEL.  We end up
       with a 0.01 ufd capacitor rated at 15,000 volts:


                       c1    c2
                       ||    ||
               |-------||----||--------|              0.01 ufd, 15 kv
               |       ||    ||        |              capacitor made from
       --------|                       |---------     four 0.01 ufd, 7.5 kv
               |       ||    ||        |              capacitors
               |-------||----||--------|
                       ||    ||
                       c3    c4


       Because the transformer has an output of 15,000 volts, and we know
       the PEAK voltages will be much higher than this, we might wonder
       whether the capacitors we just wired together can handle the peak
       spikes.  To reduce the chance of failure, we would be better off
       placing THREE of our capacitors in series to achieve a voltage
       rating of 7,500 times 3 or a total of 22,500 volts.  But what would
       our capacitance be if we do this?  Right!  The capacitance will be
       0.01 divided by three or 0.03333 ufd.  Guess what?!  We need to
       parallel THREE sets of these caps to bring the capacitance back up
       to 0.01 ufd:


                       c1    c2   c3
                       ||    ||   ||
               |-------||----||---||-----|
               |       ||    ||   ||     |            0.01 ufd 22.5 kv
               |                         |            capacitor made from
               |       ||    ||   ||     |            nine 0.01 ufd, 7.5 kv
       --------|-------||----||---||-----|--------    capacitors
               |       ||    ||   ||     |
               |       c4    c5   c6     |
               |                         |
               |       ||    ||   ||     |
               |-------||----||---||-----|
                       ||    ||   ||
                       c7    c8   c9


       Using this method, you may build a capacitor rated for any
       capacitance and at any voltage rating!  The down side is that you
       can use up a LOT of capacitors!


       Polyethylene sheeting may be purchased in Dallas from

                                  Regal Plastics,
                                 2365 Merrell Rd.,
                                 Dallas TX  75229,
                               Phone (214) 484-0741.

       Cost (8-93) is:

          .0625" thick  48" x 96"  = 17.50  each x 2 = $35  plus tax
          .090" thick   48" x 96"  = 30.00  each x 2 = $60  plus tax

       I've also bought .030" inch poly from

                                 Allied Plastics,
                             4111 Billy Mitchell Dr.,
                                Dallas, TX  75244,
                               Phone (214) 392-2708,
                     for $14.50 per sheet, not including tax.

       We will make our conductive plates  out  of  aluminum roof flashing.
       You can buy a fifty foot roll of 14 inch wide aluminum roof flashing
       here in the Dallas area from Home Depot for about $22  (4-93).  This
       is almost exactly  the  length  you  will  need for three caps.  The
       aluminum flashing, by the way, is  about  10  mils  thick.  My local
       Home Depot charged me  - $21.80 (4-93)

       For a capacitor  container,  we  will use 6 inch diameter sdr 35 PVC
       pipe cut into 19 inch lengths.  I got mine at

                             Southwestern Underground,
                            1696 W. Northwest Highway,
                                 Irving TX  75014
                                  (214) 556-0188.

       PVC pipe comes in 13 foot lengths, $1.25 per foot, or $16.25 + tax
       (2-93). You will also need flat "glue on"  pvc end caps for this
       pipe; $4.40 each, or $26.40 for six (enough for 3 caps). Do NOT  get
       the rubber gasketed end caps  - they are not flat on the end and the
       seals will not hold up once immersed in oil.

       You will also need pvc primer and cement to glue the end caps to the
       pvc pipe.

       You will also  need  some  1/4 inch  thick  clear  plexiglass  sheet
       scraps, each piece large enough to cut a 6 inch diameter circle.

       You will need plastic tie-wrap straps about 24 inches  in length, or
       enough 12 inch straps to link together to form nine 24 inch long
       straps.  Try to  get  straps  that do not contain metal teeth inside
       the lock of the strap.

       To make connection to the aluminum  plates  you  will  need some #10
       screws, washers, and nuts.  You will need two split-bolt  electrical
       connectors to go  on  the  top  of  each  capacitor  -  Home Depot,
       $3.33 each.  You will  also  need  3 or 4 feet of high voltage wire
       to  connect  the  split-bolt output connectors  to  the aluminum
       plates.

       You will need  two inexpensive radiator drain petcocks (valves) from
       Chief Auto (#852079) for $2.99 each.   We  will  use these valves to
       fill the capacitor with oil and/or attach a vacuum pump.

       Finally, you need  a  very  high quality mineral  oil  to  fill  the
       capacitor.  I use  SnapLube-100  from  Tulco Oil in Arlington Texas,
       (817) 640-0051.

       It comes in a five gallon re-sealable  pail  for  $43.10,  including
       tax.  I've never  had  an oil related capacitor failure  using  this
       oil. SnapLube 100 is a highly refined non-carcinogenic oil containig
       no PCB's.

       PCB's, poly chlorinated  bi-phenols,  are  a  very evil, nasty stuff
       which used to be used in high voltage oils - it is not something you
       want to come in contact with, especially  if you ever expect to bear
       healthy, normally formed  children.  Stay away from PCB oils.  Any
       way, just  about  any  good quality, low moisture mineral oil will
       work in these capacitors.

       ACTUAL CONSTRUCTION:

           BOTTOM PVC end caps:
           Glue two  1/2 inch by 1/2 inch square pieces of plexiglass stock
           three inches  long  across  the  inside bottom of the BOTTOM end
           caps. Make sure these two strips are at least 1/4 inch away from
           the walls of the plastic end cap!   You  have to allow space for
           the wall of the pvc pipe to reach the bottom of the end cap.

           The purpose of these spacers is to prevent the  rolled capacitor
           from sitting  directly  on  the  bottom  pvc end cap.  The space
           allows any moisture in the oil  to  settle  to the bottom of the
           cap - the capacitor will sit on these plexiglass  supports above
           the moisture contaminated oil.

           PVC case:
           Cut three  pieces  of  6  inch diameter pvc pipe 19 inches long.
           Clean the pieces with alcohol.   Prime ONE end of each pipe with
           pvc primer.   Immediately  swab bunches of pvc  cement  on  the
           bottom 3  inches  of  each pipe.  Swab the inside walls of three
           end caps which you prepared in the first step.  IMMEDIATELY push
           an end cap onto the glue coated  end of each of the three pipes.
           YOU WILL NOT GLUE A CAP ONTO THE TOP OF EACH PIPE YET - JUST THE
           BOTTOMS!  As you push the bottom end caps on, twist them to help
           insure a good seal.

           Take the remaining three end caps which will  be  used  for  the
           TOPS of  the  capacitors.   Using  a  saber  saw cut a five inch
           diameter hole in the end of each cap. This will leave a 1/2 inch
           pvc border  surrounding  the  hole.   Cut  three 6 inch diameter
           circles out of your 1/4 thick plexiglass stock.

           Next, we will score the TOP of the plexiglass with a sharp metal
           scribe in the shape of a big X,  going from edge to edge.  Below
           is a crude picture of these two cuts.  Make the  scribe marks at
           LEAST 1/32 inch deep.

                                /===========\
                               /\            \
          Cut two scribe      /   \         / \
          marks at right     |      \     /    |
          angles to each     |        \ /      | <-- TOP of plexiglass
          other.             |        / \      |     capacitor cover
                              \     /     \   /
                                \ /         \/
                                  \========/

               *************** Important Safety Note *******************
               The purpose of the scribe marks is to provide starting
               places for CRACKS to occur should the capacitor fail and
               excess pressure occur.  The plexiglass will bow outward
               and crack at the scribe marks, releasing pressure.  MAKE
               SURE THAT THE SCRIBE MARKS ARE ON TOP WHEN YOU INSTALL
               THIS COVER!
               *********************************************************

               Use pvc cement and glue a 6 inch plexiglass disk over the
               hole you just cut in the end of the top cap. MAKE SURE
               THE SCRIBE MARKS ARE ON TOP!  Do this for all three top
               end caps.  You just created three TOP end caps with clear
               windows in the ends!

               *************** Safety Notes *************************
               The plexiglass will seal to the pvc, but pvc cement does
               not effectively bond plexiglass to pvc.  This is good!
               Should the capacitor experience a pressure buildup due to
               electrical failure we WANT the plexiglass to crack and
               come loose and let the gasses out!  The plexiglass cover
               also allows us to SEE a capacitor failure - the light
               from the arc shines out!  The plexiglass cover serves as
               at least two important safety needs!  Do NOT build a
               capacitor without this or some other form of over-
               pressure release mechanism!
               ******************************************************

               *** Now let all pvc cement dry for 24 hours before doing
                   any additional work on the pipes or end caps!  See "PVC
                   CONTINUED" below  for  completion  of  the  TOP end caps
                   after the glue has dried.

               Aluminum:
               Cut your aluminum flashing into six pieces, 14 inches
               wide (natural width) by 93 inches long.  Use large
               scissors to make cuts.  Cut all corners round (use a
               fifty cent piece to mark the curves on the corners) to
               reduce corona. Using a hand operated paper hole punch
               (any office supply has these), punch a hole in ONE end
               of EACH sheet, about 1/2 inch from the end, midway between
               the end corners.  Take wet/dry sandpaper and sand all
               burrs and rough edges off the flashing. Preparation of
               the aluminum edges and corners is VERY important!  Any
               burrs or roughness will result in capacitor failure!

               Attach a length of high voltage wire to the hole in the
               aluminum using a wire terminal and # 10 hardware.  The
               wire should be about 16 inches long.  Do not do anything
               with the other end of the wire yet.  Cut your screw off
               as short as possible, very close to the nut.  DO NOT GET
               METAL FILINGS OR METAL DUST ON YOUR ALUMINUM FLASHING OR
               POLY!  METAL DEBRIS MEANS CAPACITOR DEATH!

               Poly sheet:
               Place sheets of newspaper on a carpeted foor.  Put one of
               your poly sheets down on the newspaper and clean both
               sides with paper towels and alcohol. Measure a line 16
               inches from the edge.  Take a magic marker and draw a
               line down the length of your sheet, 16 inches from the
               edge.  Go to the opposite edge and do the same, drawing
               another line down the length of the sheet.  Your poly
               sheet should now be marked into THREE equal pieces, each
               16" by 96".  Using a box knife, carefully cut along these
               lines.  You will have three pieces 16" by 96" long.  When
               you complete these two cuts, carefully set the three
               pieces aside on a clean piece of paper.  Next, clean,
               mark and cut your second piece of poly stock into three
               pieces.  It is important that the poly you use is
               scratch-free and umblemished!  Any imperfections can
               cause capacitor failure.  You now have six 16" by 96"
               pieces of poly (again, if you are layering your poly, you
               will have several times this number of sheets.)

               Assembly:
               Place a 16" by 96" length of poly on your newspaper.
               Place one of your aluminum sheets on top of this first
               poly sheet.  Align the aluminum so that you have an even
               1 inch border of poly showing all the way down it's 93
               inch length.  Now scoot the aluminum towards the screw
               end so that the aluminum hangs over the END of the poly
               one inch.

                           Note the 1 inch overlap of
                           the aluminum end over poly!     | |

                                     Top
                    |--------------------------------------|
                    | |=======================================
                    | |                                      |
            Poly--->| |    Aluminum sheet #1                O|<--hole and
                    | |                                      |   screw for
                    | |                                      |   wire
                    | |                                      |
                    | |=======================================
         Left       |--------------------------------------|    Right
                                    Bottom

               Place poly sheet #2 on top of the first aluminum sheet.
               Align this poly exactly on top of the first poly sheet.'


               Place the final aluminum sheet on top of the second poly
               sheet.  The screw end should be on the far end of the
               capacitor, OPPOSITE the first screw.

                  | | Note the 1 inch overlap of the
                      end of the aluminum over the poly!

                                 Top
                  |--------------------------------------|
                  |======================================= |
                  |                                      |  |<-  Poly sheet
        Hole & -> |O       Aluminum sheet #2             | |
        screw     |                                      | | (poly and alum
        for wire  |                                      | |  sheets #1
                  |                                        |   |    omitted
                  |======================================= |  for clarity)
        Left        |--------------------------------------|  Right
                                   Bottom

          You should  have  a capacitor sandwich consisting  of,  from  the
          bottom of the stack up, poly, aluminum, poly, and aluminum.  Make
          sure that the screws on the two sheets of aluminum are NOT ON THE
          SAME END OF THE CAPACITOR!

          Now carefully  roll  the  capacitor up, starting on the left end.
          Make the core hole in the center  of  the  roll  about  2  inches
          across.  Roll  the capacitor up as TIGHT as possible!   KEEP  THE
          BORDERS ON  EACH SIDE OF THE ALUMINUM STRAIGHT!  If your aluminum
          gets too close to the edge of the capacitor, high voltage can arc
          around the  edge of the poly, causing  catastrophic  failure.   I
          really suggest  getting  a helper to help keep  things  lined  up
          straight as you roll!

          Once the  capacitor  is  rolled up, you should have a cylinder 16
          inches tall and about 4.5 to  5  inches  in  diameter.   If  your
          capacitor is much over 5 inches in diameter, then  it  won't  fit
          inside the PVC pipe.

          Take three  plastic  tie-wrap straps and tie the rolled capacitor
          up so that it can't unroll.  The two wires should come out of the
          top of the capacitor - one from  the  inside  of the roll, one on
          the outside.  Place a scrap piece of poly between the head of the
          screw and  the  underlying  poly  sheet so that the  screw  won't
          puncture the underlying poly sheet.

               PCV PREPERATION CONTINUED:

               Carefully slide your rolled capacitor into one of the pvc
               pipes, making  sure  the  wires  are  "up".  You should have
               about a 1/2 inch space between the outside of your capacitor
               and the inside wall of your  pvc  pipe.   The capacitor will
               sit on the two plexiglass spacers which keep  the  capacitor
               1/2 inch above the bottom of the end cap (see step one).

               Take two of the split-bolt connectors and set them on top of
               the plexiglass  window  on the TOP end cap.  The head of the
               bolt will sit on top of the plexiglass.  Place the two bolts
               opposite each other, about 5 inches apart.


                                /===========\
             Split bolt ---->  /      O      \
                              /               \   <-- 6 inch round cap with
                             |                 |        5 inch plexi window
                             |                 |
                             |                 |
                              \               /
             Split bolt ---->   \     O      /
                                  \========/

               Mark the  plexiglass with a marker right around the edges of
               the bolt where it sits on  the  plexiglass.  Next, clamp the
               bolt in a vise.  Drill two holes through  the  head  of  the
               bolts.  We  will  use  two 1.5 inch long # 10 screws through
               these holes to attach the bolts to the plexiglass.

               Take the plexiglass window and prepare to drill holes in it.
               Place a drilled split-bolt on the plexiglass where we marked
               it earlier, and mark the  new  hole  positions on the plexi.
               Drill the two holes.  Coat the bottom of the split bolt with
               epoxy and attach the split-bolt connectors to the plexiglass
               window with  1.5  inch  # 10 hardware as shown  below.   The
               epoxy is  important to prevent oil leaks. Place epoxy on the
               screw threads where they  pass  through  the  split bolt and
               where they pass through the plexiglass:


              ||     ||      <--  SPLIT BOLTS -->       ||     ||
              ||     ||                                 ||     ||
              || === ||                                 || === ||
              ====|====    < --- glop epoxy!    ----->  ====|====
           =======|=========================================|======<--plexi
           =======|=========================================|======   glass
          nuts ->===                                       ===
                  |          <--   SCREWS  -->              |
                  |                                         |

       Note: each split-bolt is held on with TWO sets of screws and nuts!

            Next, we drill and tap two holes in the plexiglass  window  for
            our two  valves.   Locate  the  holes  for  the valves as shown
            below:

                                /===========\
             Split bolt ---->  /      O      \
                              /               \   <-- 6 inch round cap with
                             |                 |        5 inch plexi window
             Valve holes --->| O             O |
                             |                 |
                              \               /
             Split bolt ---->   \     O      /
                                  \========/

             This arrangement keeps the split-bolts far apart, and the
             two valves will be far enough away to prevent problems.

             The holes for the valves should be slightly smaller than
             the threaded portion of the valve.  Be very careful tapping
             the plexiglass else it will split!

             Coat the threads of the threaded end of the valves with
             epoxy and screw the valves into the holes.  The epoxy will
             seal the threads closed to the plexiglass and will prevent
             oil leaks.  Do not get epoxy inside the valve itself!

             Give the expoy a several minutes to dry.  Hold the end cap
             over the top of the capacitor.  Test it to see how it fits
             down over  the  6 inch pvc pipe.  Make sure the screws holding
             the split-bolts do not come  too  close  to  the  top  of  the
             capacitor.  Lift the end cap off the capacitor.  The wire from
             the inside of the capacitor will connect to  a  screw  on  one
             split-bolt connector;  the  other wire from the outside of the
             capacitor will connect to the OTHER split-bolt connector.

             Measure and  cut the wires  so  that  they  are  as  short  as
             possible, YET  STILL LONG ENOUGH TO REACH THE  SCREWS  HOLDING
             THE SPLIT-BOLTS.   Crimp and solder a round terminal connector
             on the end of the two capacitor  wires.   Attach  each wire to
             one of the split-bolts using another couple  of  #10  nuts and
             washers.

             Again, temporarily slide the top end cap on and check your
             wires for fit.  If all looks ok, it is time to glue this
             puppy on!

             First, open both vlaves so air can go through them.  If you
             forget this step, you won't be able to push the TOP down
             over the pipe because of the trapped air!

             Slather the outside top three inches of your pvc pipe with
             primer. Coat the inside walls of the end cap with primer
             too. Next, coat over the primer with lots of pvc cement.
             Quickly push the cap on the pipe, twisting back and forth
             to make a good seal.

             Connect a vacuum pump to one of the valves with a length of
             5/16 hose.  While running the pump, apply additional glue
             around the lip of the cap where it touches the pipe. Listen
             for the hiss of air getting sucked in.  If you find a leak,
             add pvc cement until it stops.  Now is the time to find and
             fix any leaks!  Once oil is introduced into the capacitor,
             leaks cannot be sealed with cement - the oil will prevent
             bonding!

             Once you are satisfied the capacitor is leak-tight, let it
             sit for at least 24 hours to allow the pvc cement to
             completely dry.  DO NOT PUT OIL IN A FRESHLY GLUED PIPE,
             OR YOU WILL HAVE ONE HELL OF A MESS!

             After the glue has completely dried, test the end caps for
             complete seal one more time.  DO NOT TEST FOR LEAKS BY
             PRESSURIZING THE PIPE!  PRESSURIZING THE PIPE CAN RESULT IN
             A VERY DANGEROUS EXPLOSION SHOULD THE PLASTIC FAIL!

             Once you  are  satisfied the plastic-to-plastic seals are good
             we can charge the capacitor with oil.  Run a 5/16 rubber hose
             from one valve on the cap to a vacuum pump.  Pump the cap down
             for one hour.  This will help boil out any residual moisture
             and will help remove air from between the layers of poly and
             aluminum.  Once it has been pumped down, run another 5/16 inch
             rubber  hose  from  the other  valve down into the 5 gallon
             pail of oil - but do NOT open this valve yet.  Turn your
             vacuum pump on.  This will help to continue to produce a
             condition of reduced pressure in the capacitor.  VERY slowly
             open the oil valve just a tiny bit.  This will cause the oil
             to flow up the hose from the pail through the oil valve into
             the capacitor!

             WARNING:  Do  NOT allow  oil to enter the vacuum pump or
                       permanent damage to the pump can result!

             *** Be sure to slowly open the oil valve - the oil will want
             to foam up and enter the vacuum pump.  Regulate the flow of
             oil so that the oil does not foam. Stop the flow of oil once
             the poly capacitor is under about 3/4 inch of oil.

             Close the oil valve completely and let the vacuum pump suck
             air out between the plates of the capacitor.  Again, the
             oil will want to foam up from all the entrapped air, so you
             will have to monitor the vacuum valve very closely to
             prevent oil from foaming up and entering the vacuum pump.

             After a half hour or so, most of the air will be out of the
             capacitor - at least enough where you can open the vacuum
             valve so that the vacuum pump is going wide open.  Be aware
             that you will get air bubbles coming up out of the
             capacitor even if you pump from now on 'til doomsday!

             You will actually suck air THROUGH microscopic channels in the
             pvc pipe and end caps!  Your goal is to get as much air out
             of the capacitor as is practicable - usually a couple of
             hours of vacuum pumping will do the job.

             After the capacitor has been  thoroughly pumped down, shut off
             the pump, disconnect the hoses.  Slowly open one of the valves
             and let air into the space above the capacitor  to relieve the
             vacuum.  Close   both  valves  on  the  capacitor  to  prevent
             additional air and moisture from entering the capacitor.

             Next comes the really hard part:  set the capacitor aside
             for at least one week, preferrable two weeks.  Two or three
             times a day, gently rock the capacitor from side to side.
             This will help air bubbles to rise.  DO NOT AGITATE THE OIL!
             The idea to remove air bubbles, not introduce more!

             ***********************************************************
             DO NOT ATTEMPT TO USE THE CAPACITOR IMMEDIATELY AFTER
             PUMPING IT DOWN!  If you do, entrapped air will cause it to
             fail.  I have learned this the hard way!  The capacitor
             needs to sit for one to two weeks to allow air to rise out
             of the capacitor.  The number one reason for premature
             failure of a new capacitor is due to running the capacitor
             with pockets of air trapped between the layers.
             ***********************************************************

             To break in your capacitor do the following:

             Wait the required week or two weeks (see above).

             *** Open one or both of the valves to act as additional
             pressure relief ports in case the capacitor does fail.

             ************ Important Safety Note **********************
             Set up the capacitor in a protected outdoor area.  Make
             sure kids, pets, nosey neighbors, etc. cannot get shocked
             from the capacitor or test transformer.  It is important
             that the chosen test sight be outdoors because the capacitor
             will be on high voltage for an extended period of time, and
             you probably won't be around should the capacitor fail.  If
             the capacitor experiences a failure, and if power is not
             IMMEDIATELY disconnected, there is a very real chance for
             an oil fire!  Better the fire burn a hole in your lawn than
             to burn your house or business to the ground!
             **********************************************************

             Attach a neon transformer controlled by a Variac (variable 115
             volt transformer) to the capacitor.  You may also use a
             variable high voltage d.c. power supply, but the "hum" from
             a.c. helps shake bubbles loose.  Slowly bring the high voltage
             up to about 50% of the capacitor's rated voltage.  Let sit for
             eight hours.  During this time, you will see additional air
             bubble up out of the capacitor.

             Air is a very real enemy!  After this 8 hour time, slowly
             bring the voltage up to 75% of the rated voltage.  Let sit
             another 8 hours. Finally bring up to rated voltage and let
             sit for 30 minutes.  If the capacitor is going to fail, it
             will usually do so by this time.

             Failure can    result   from   poor   quality   or   imperfect
             polyethylene, insufficient  poly  thickness,  burred  aluminum
             edges, oil containing moisture (1 part water  in  10,000 parts
             oil reduces  the  oil's  insulation  factor  by  50%  !!!)  or
             entrapped air.   Insufficient   border   spacing   around  the
             aluminum can also cause capacitor failure.

             It is highly suggested that you open one of the valves on
             the capacitor when using with a Tesla coil or other high
             peak power source in case the capacitor should fail.

             Having a valve open will vent a sudden build-up of pressure
             from the gases which come from the vaporized plastic which
             occurs when a capacitor fails.  Close the valves whenever
             the cap is NOT in use to prevent moisture in the air from
             entering the capacitor.

             The capacitor should be stored and transported standing
             upright.  If the capacitor gets turned on its side, the air
             in the space above the capacitor will get back into the
             layers of poly and aluminum - and you don't want to have to
             go through the pump/wait process again!

             Theoretically you could completely fill the capacitor with oil
             - providing you left a way for the oil to expand and contract
             with temperature changes, AND if you could build a 100% sealed
             PVC container.   I assure you that doing this is harder than
             one would suspect!  The pvc end caps may  seep  a tiny amount
             of oil THROUGH the plastic - pvc is not nearly as impermeable
             as we would be led to believe! Stand the caps upright in a
             large metal pan to contain any oil leakage.

             The pan should be large enough to contain all  the  oil stored
             in one  of  the capacitors.  The pan will contain leakage, and
             should you have a capacitor  container  failure  and oil fire,
             the pan will contain the burning oil - definitely a plus!

             Again, remember one reason why we put a clear plexiglass
             window on the top of the capacitor: it lets you see when
             you have a capacitor failure!  If the capacitor fails, the
             high voltage arc will be visible through the clear window.

             If you do have a capacitor failure, DISCONNECT POWER
             IMMEDIATELY!  FAILURE TO DISCONNECT POWER CAN RESULT IN A
             CATASTROPHIC CAPACITOR FAILURE!  DANGERS INCLUDE EXPLOSION
             AND AN INTENSE OIL FIRE!


             ************** LEARN FROM MY MISTAKES! ******************
             Due to impatience, I did not let some of my capacitors sit for
             a sufficient time before use, so they had air trapped in the
             layers.  They failed. I built several capacitors with
             poly which was not thick enough to withstand the voltage of my
             transformer. They failed.  In every case I quickly
             disconnected power.  Not once have I had a "catastrophic"
             failure resulting in container failure or fire.  But I ALWAYS
             keep a fire extinguisher rated for oil fires handy, just in
             case!  So should you.