[Boatanchors] Capacitor Dissection

[Richard Knoppow]

     I dissected a Cornell-Dublier "Cub" capacitor.  This 
one had quite high leakage. I don't remember what it came 
out of and it may have just been an old unused one.  These 
are black molded cases and look a lot like Black Beauties. 
It also has what appears to be an oil filler tube at one 
end.
     I cracked it apart in a plastic storage bag.  It came 
apart with considerable difficulty as opposed to the BBs 
I've dissected in the past which cracked apart easily. 
Actually several of them were already cracked and falling 
apart.
     The Cub is generally similar, a wound structure of 
aluminum foil with a dielectric that looks like paper 
impregnated with a lacquer but is probably plastic. The 
paper is thin, translucent, and amber colored. The aluminum 
sticks quite tenaciously.  I unwound enough of it to see the 
structure. I could not get at the core or even tell for 
certain if there is a core.
     The winding was wrinkled throughout but not squashed as 
were all of the BBs I've taken apart.  There was no sign of 
oil or that there ever was any so I am not certain if the 
filler tube is really that or only a method of fastening the 
outside foil.
     It would be interesting to know what the windings 
looked like before being encased; that is, were they 
wrinkled or not.  If not the molding process must have done 
it. The same thing with the BBs, were they squashed as a 
method of adjusting or did the molding or later stress do 
it?
     I think my AR-88 may have some flat paper caps in it. 
If so they will be replaced and I will dissect one to see 
what is in it.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com