[Boatanchors] [BoatAnchors] [Milsurplus] Micamold Recovery

[L L bahr]

Hey Dave,

Good luck with your venture.  I'm one of the guys who frowns on using them.  However, tat said, your logic is sound.  Just different strokes for different folks.  I am usually a stickler for keeping things stock and original, but when it comes to caps, I go for the new ones.  You can't see them once the radio is back in the case, they are electrically superior and very cheap to buy these days.  A couple years ago I refurbished a Johnson Viking I and I think it had 21 of them in there as I recall.  Everyone of them was bad and actually was producing a voltage as if it were a battery.  I replaced all of them with disc ceramics, but that story in itself would bring on many positive and negative comments from some.  Anyway, just wanted to let you know even though I would not use them, your topic was interesting and you have the right to try things that interest you and do things your way. The most important thing is too have fun doing what you are doing in ham radio.
Lee, w0vt  

----- Original Message -----
From: "David Stinson via BoatAnchors" <boatanchors at theporch.com>
To: boatanchors at mailman.qth.net, milsurplus at mailman.qth.net
Sent: Wednesday, June 4, 2014 2:00:28 PM
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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