[Boatanchors] [Milsurplus] Micamold Recovery

[David Harmon]

>> or if they pop like popcorn after a week, I'll let ya know.<<

Don't bother.....everyone else in the world already knows.


73

David Harmon
K6XYZ
Sperry, OK

-----Original Message-----
From: Boatanchors [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of
David Stinson
Sent: Wednesday, June 4, 2014 2:00 PM
To: boatanchors at mailman.qth.net; milsurplus at mailman.qth.net
Subject: Re: [Boatanchors] [Milsurplus] Micamold Recovery

Thank you for all the input.  I do understand the "conventional wisdom"
concerning MicaMolds,  but I'm not convinced just yet.  
Here's why:  These caps were all produced about
70 years ago and have been taking-up water at about the same rate.  They
have been aging as a group.
Capacitors or coconuts- age a group of things produced at about the same
time and they'll all be in about the same shape.

We got them over the last 20 of those years.
Many of them have taken-up water (as would be
expected) and test "bad."
We've had to change them, leading us to curse them and just change them all-
it's only human nature.
But, as far as I know, no one has tried to drive the water out, re-seal them
and see if they can make another
50 years (or better, since we have better stuff to seal them).

I like the way they look and I like the possibility of "original
replacements."  Got nothing to lose but a little 
time and effort.   So here's what I plan to do:
Coat the "dried-out" caps with varnish or poly..
anyone know which is a better water barrier?
Then build a low-freq oscillator using all of this handful of caps, plug it
in and leave it running for a loooooong time.  Like two years.
See what the "mean time between failures" 
really is.  If they stay in service with no failures for a year or two
(which passes quickly at our age) or if they pop like popcorn after a week,
I'll let ya know. 

73 DE Dave AB5S

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