FIRST capacitor, please advise/help

From: 	Sulaiman Abdullah[SMTP:sulabd-at-hotmail-dot-com]
Sent: 	Thursday, December 04, 1997 3:54 AM
To: 	tesla-at-pupman-dot-com
Subject: 	FIRST capacitor, please advise/help

Hello all,  I sent an e-mail with attachments that got screwed-up,
so here's my request again. Please send me any comments/thoughts.

I'm building my FIRST Tesla Coil, 
I have built, and destroyed, a couple of small/test capacitors.
Now I'm building my FIRST real primary capacitor.

My power source is a 15 kV centre-tapped 30 mA 50 Hz NST.
I calculated 6.3662 nF as the optimal value to match my NST.
The design is a basic vertical stacked-plate, in oil.

DIELECTRIC 22 pieces of 300mm x 300mm x 3mm HDPE.

PLATES     23 pieces of 280mm x 250mm x 0.4mm Aluminium.

SPACERS    21 pieces of 1" x 1/4" x 300mm Aluminium stock.
            2 pieces of 1" x 1/4" x 400mm Aluminium stock.
                (300mm plus 100mm for external connection)
            2 pieces of 1" x 1/8" x 300 mm Aluminium stock.
                              ( for two ends of capacitor)

OIL         not yet decided.

When all these pieces are assembled there will be 22 parallel plates
of effectively 250mm x 200mm for a total theoretical value of
22 x 8.854 x 2.2 x 0.25 x 0.20 / 0.003 = 7.142 nF.
The tracking/arcing distance should be 50mm at the ends,
and 2 x 25mm upand down.

If you can understand the above then please help me by pointing
out anything that should be changed before I assemble it.
Questions that come to me are ;

1 Is 50mm at the ends enough?

2 Is 25mm at the top/bottom enough?

3 Based on your EXPERIENCE how many kV should such a capacitor
   be able to handle.

I'd rather have a long-lasting pulse-capacitor than one of the
theoretically correct value, so I'm willing to trim the plates as 
you may reccomend.

I really want this to be a long-life component as I immagine other uses 
in future such as high-power high spark-rate RSG Tesla use,
can-crusher,magnetisation pulses etc.


Thanks ... Sulaiman