rolled cap blowew out

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Adriano.Mollica@xxxxxxxxxxx 


Hello list,

after the last attempt to start the TC using lithuanian capacitors, 
that used to explod very quick and very often, i made a homemade 
rolled polyethylene cap.
The dielectric thickness was 0.4 mm, since 1 mm should resist 60kv, i 
thought that 0.4mm should handle about 25kv.
After the rolling up of the materials, i dip the roll into a tube 
filled with synthetic engine motor oil, and by a vacuum pump i 
removed all the air inside.

unluckly, after few successful sparks, the capacitor stopped working 
and started to make a noise (probably an internal arc).
i'm pretty disappointe 'cause i spend around 40 euros in materials, 
and many hours of work!

how can i built a cheap, reliable, and FAST pulse discharge capacitor?

i'm thinking about planar caps in air ( at least is the cheapest 
dielectric i know.!

any suggestion?

how much is the dielectric costant of the air, and its puncture voltage?
37 nF cap wil probably be very large?
thanks!