capacitor find

From:  Hollmike-at-aol-dot-com [SMTP:Hollmike-at-aol-dot-com]
Sent:  Sunday, June 28, 1998 12:39 AM
To:  tesla-at-pupman-dot-com
Subject:  capacitor find

Hi All:
    I recently removed a large cap from an RF generator, but I don't think
that it was from the part of the circuit that generates the RF.   It seemed to
be part of a 2600V dc circuit that powered the RF generator.   I was hoping
someone on the list could tell me anything about it.  What is printed on the
side is as follows:

          KNOC 4M  25
             25 MFD
   This is obviously a 200J cap, but my question is: what is the dielectric?
It seems like it could be polypropylene, but could just as easily be Mylar.  I
desoldered the lid from the can and found three extended foil caps in parallel
using about 1.25 inch wide tin(?) strips soldered to the ends of each.  I, of
course, cut the strips in order to change them to a series configuration to
get a 2.7uF(measured), 12kVDC cap.  
    My hope is to be able to use this as either a tank cap for induction
heating or even as part of a TC primary cap.  Does anybody know if this will
work as such?  I am hoping that even if the dielectric is Mylar, that the high
power rating will allow it to be used without overheating since I would only
be applying a small fraction of the power that the RF generator was designed
for(less than 1/10 of what it is designed to handle).
   Thanks in advance for any info you can give me.
Mike Hollingsworth