[Milsurplus] Bathtub Capacitors

[gl4d21a at juno.com]

John:

I would be very careful in trying to establish a generality here. Examination of sales literature of the era shows there were a plurality of manufacturers, and what worked for one may not ...etc.

With that preamble, all the tubs I have rebuilt have been apparently 60/40 solder dipped brass.  Certainly not pure zinc, that is galvanizing, and it ain't that.  Nor pure tin as some food cans were back then, the finish is wrong.

Now, as far as fill is concerned, there has been practically a flame war over on the RCA reflector about whether they were PCBs or not.  Simple test: soak the end of a Q-tip in it and see if it will burn.  I've never found one which did not, so that leaves out PCB, which were used in the larger capacitors to be non-flammable.  Mineral oil is another non-specific generality.  Likely not vegetable oil-HI!

I would be very surprised to see any correlation between topology and failure rate.  The design of the capacitor itself, foil covered oil soaked PAPER guarantees eventual failure, don't you think?  What oil lasts forever?

HTH
73
George
W5VPQ


---------- Original Message ----------
From: "J. Forster" <jfor at quikus.com>
To: ARC5 at mailman.qth.net, Milsurplus at mailman.qth.net
Subject: [Milsurplus] Bathtub Capacitors
Date: Wed, 15 Feb 2012 10:39:14 -0800 (PST)

Hi,

Does anybody know:

What are the cans of WW II bathtub capacitors made of? Brass or Steel?

What is the plating? Tin? Zinc? ??

What kind of oil was used to fill them? Mineral? Something chlorinated?

Is there an increased failure rate on caps with one side electrically tied
to the case v. those with both terminals of the cap floating?

Thanks,

-John

____________________________________________________________
53 Year Old Mom Looks 33
The Stunning Results of Her Wrinkle Trick Has Botox Doctors Worried
http://thirdpartyoffers.juno.com/TGL3131/4f3c1eb7af85d14978fast06duc