[ARC5] Re-stuffed cap

[John Hutchins]

Ken -
To bad an electric can opener could not be used to open then close the 
lips on these puppies?
Some one with a lathe could make an slope-ie L shape to open then pop 
the wheel off and lay down  L to  close them up.

Electric can opener?

-Hutch


On 3/30/2011 1:36 PM, Kenneth G. Gordon wrote:
> Later this evening, I'll post the article and photos of my latest re-stuffing job
> to my website.
>
> Although this first attempt looks "acceptable" and works well, it does not look
> as good as I think I can make them. I would like to make them look identical
> with the originals, but may not be able to.
>
> I am working on another one, which, by the way, was made by Aerovox. The
> previous one was made by Sprague. Both appear to have been built
> identically, probably according to either A.R.C. or military specifications.
>
> However, the Aerovox cap was MUCH more deteriorated, both internally and
> externally, than the Sprague. All the individual caps in the Aerovox cap were
> completely "soaked" in green corrosion, and the connections to the ends
> were all loose. They ALL came loose with a very slight tug on the leads, and
> the interior of the brass pot was covered in green corrosion, which was very
> difficult to clean out.
>
> I have tested the Sprague cap that I finished, and have found some
> interesting things:
>
> 1) there is considerable capacitance measurable BETWEEN each of the
> three disk ceramics, even the "outside" two, in the restuffed cap: about 0.025
> mfd between EACH 0.05 mfd cap, almost exactly 1/2 of the capacitance of
> each individual cap. I installed all three disc ceramics "facing" the same way.
> In the next one, I'll reverse the center one to see if that makes any
> difference.
>
> 2) When measuring the originals, there was ALSO just about 1/2 the rated
> capacitance between each of the paper caps. I wonder if this was a
> "designed-in" feature of the original circuitry? If it was, i wonder what its
> purpose was intended to be? Maybe it doesn't matter?
>
> 3) There is no measurable leakage at 450 VDC (the upper limit for my C-3)
> between any of the three caps. The capacitances between them, again
> 0.025 mfd, have identical leakage as that of each individual cap....essentially
> none.
>
> 4) Although I did this first job in several sessions, I suspect that if I were to sit
> down and complete one, from start to finish, it would take a little over 1 hour
> apiece.
>
> Does anyone know that these brass pots were plated with? Zinc? Some
> other metal?
>
> Is it worth it? I don't know, but it is certainly interesting...
>
> Ken W7EKB
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