Re: Why do my caps keep blowing?

>I am making them from 1mm thick poly (10layers of 100um)

First off thats only 10 layers of 1mil thick poly, or 10 mils.  Each mil
is good for around 300 volts, so your capacitors are only rated at
3000 volts.  Thats why they die.

>When I place 12kv30ma a.c. across them (0.008uf)  with no load to test them
>they puncture through the middle of the poly within 5 minutes.
>Perhaps I shouldn't test them like this?

I constructed my cap using 3 caps in series, each one used 4 layers of
6 mil poly, 24 mils per cap, or 72mils total.
74x300=22200volts, and believe me that capacitor has been taking a beating.
I had my first one last 6 months, and this one is built alot better, will
last alot

>What is the life of one of these caps anyway?

>When I have constructed my coil I want maximum life out of the caps so how
>long should I set for each coil run?

If constructed correctly, they will last along time.  Mike Hammer I believe
had his caps for 2 years.

Coil runs at first should be limited too 20-30 seconds while the cap breaks
Afterwords, runs up to five minutes will be maintainable, although I seldom
mine for more than 3 minutes, with a few minutes between runs for cooling.