[Milsurplus] Recovering "Bumble Bee" Capacitors

[Brooke Clarke]

Hi Dave:

Would you send me a couple of the non baked caps?
I've just started a web page mainly aimed at ESR issues, see:
http://www.prc68.com/I/Capacitors.shtml
and would like to see if leakage also shows up in other parameters.

Have Fun,

Brooke Clarke, N6GCE
http://www.PRC68.com


> Date: Wed, 17 Mar 2010 13:47:06 -0500
> From: "David Stinson"<arc5 at ix.netcom.com>
> Subject: [Milsurplus] Recovering "Bumble Bee" Capacitors
> To: "Old Tube Radios"<boatanchors at theporch.com>,
> 	<milsurplus at mailman.qth.net>
> Message-ID:<8AC947A8313042CEA70FE3348F8A70F9 at boudreaux>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
>
> At a recent hamfest, I bought a large bag of NOS Sprague
> .1 uFd, 400 volt "Bumble Bee" capacitors, the ancestors of
>   the "Black Beauty" type, for $3.
> All of them were, of course, leaky to one degree or the other.
> I took a handful of the worst leakers and put them in the stove
> at 250 degrees for one hour.  The cases split, of course,
> and a small amount of wax pooled under them.
> I let them cool overnight and checked them again.
> To my surprise, they check excellent!  Every one of them
> came back.  At full voltage, they are in spec for capacitence
> and leakage is less than 10-20 microamperes at 400 volts.
> Of course, with the cases split, they'll absorb water again.
> I'm thinking of resealing with liquid tape or the like.
> I have quite a few more of them left.
> Perhaps if I use a lower temp and longer time,
> I can "dry" them without splitting the cases.
>
> 73 Dave S.
>
>
>