[Milsurplus] Recovering "Bumble Bee" Capacitors

[J. Forster]

IMO, 250F is way too hot. I'd try something like 150F for eight hours or
more. That will dry them out inside and allow the water vapor to escape.

Best,
-John

===============



> 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.
>
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>