Richard Knoppow wrote:

All the BBs I've seen had colored stripes indicating
the capacitance value and other data. These were dry caps.
Not dried out oil-filled, there was no trace of oil or means
of adding it.

Richard, All BB's with color bands made in the late 40's,
through the '50s were oil filled. The filler was not all
that obvious unless you knew what you were looking at. It
looks like a little solder ball on the banded lead where
it enters the case. The cases look like bakelite, but I am
not sure that they are. Bakelite requires high temperature
and high pressure to cure (hence the "bake"). I don't think
that would be good for a plastic dielectric capacitor.

By the early '60s Sprague had thoroughly taken a drubbing over
the failures of the BB's, and changed them to be a plastic
dielectric, like the OD's.

I don't think I have ever found a bad OD; nor have I ever found
a bad BB that wasn't of the oil filled variety.

-Chuck


According to Sprague advertising of the time (early
1960s) the BB and Orange Drop had identical construction
other than the encapsulation and radial leads on the ODs. I
don't have catalogue info giving prices. The ODs were
evidently made for printed circuit installation as you say
and were probably smaller due to the dipped rather than
molded case. I am not sure what the case of the BBs is made
of, it appears to be a resin plastic such as Bakelite which
was widely used at the time. Bakelite can shrink and depends
very much on the filler used for longevity. They may have
been made of something else. In any case, its of academic
interest now. I remember having been warned not to use BBs
as early as highschool, meaning the late 1950's. Also, the
Hammarlund receivers began to be rebuilt with disc ceramics
about the late 1950's so the trouble must have shown up
within a few years. Sprague continued building the cap so,
perhaps, the cause of the problem was discovered. They
_should_ have been a superior capacitor. Too bad.