I have made many glass-and-foil capacitors over the years
for Tesla Coil projects. We built huge ones from greenhouse
panels. It took days to charge them; 2 kvs, but MANY farads
of storage. We would discharge them thru copper pipes
that would vaporize with a loud bang. Thousands of amps,
just like lightning.
 Your old one there may be glued together, they used varnish
in those days. But, if you can measure the thickness of the
glass, and square inches of foil, you can calculate the capacitance
by formula quite accurately. Only error you may have is that newer
glass will have a different dielectric constant than old glass.
But, don't be afraid to try. No big deal. -pat
*     Pat Masterson   D12-25  | KE2LJ-at-KC2FD                 *
*     Grumman Data Systems    | 516-346-6316.               *
*     Bethpage, NY 11746      | bat-at-gdstech.grumman-dot-com     *

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