Depending on the size of your cap, you might try changing your cylinder
from a closed-ended cylinder to an open cylinder.  You can solder your
capacitor and clean it.  Then solder the end cap on.  I'm assuming there
is a pin running through the cylinder; your end cap will need a glass
seal to insulate the pin from the cylinder wall.

Also you may want to try using a tunnel oven with Nitrogen atmosphere
and no flux.  This works in some applications.  You may need to use
fixtures and weights.  This usually requires much process
experimentation.

Lastly, I've had success with IR at temperature when I've carefully
metered out the quantity of flux in the application.  Minimizing flux
and using plated surfaces and low solids "R" flux was necessary.

good luck

 ----------------------------
Name:     Isaak Baber
Company:    Oceana Sensor Technologies
E-Mail:    FLG8RZ.aol.com

Comments:

 We are currently soldering a cap to a cylinder and are creating a
closed space.

We have tried several solder pastes and wires (43Pb 43Sn 14Bi) with a
no-clean
flux included. These solders came from a variety of companies including
Alpha
Metals, Indium Corp., AIM, and ESP.
We found that when the no-clean flux is trapped in a closed space the
surface
insulation resistance at a temperature of 250 deg F drops by several
orders of
magnitude. We believe this is due to volitile organic content contained
in the
flux. We have found that by placing a small hole in the wall of our
closed space

(which acts like a vent) prevents the surface insulation resistance from
dropping and we maintain the same insulation resistance that we have at
room
temp. However, making a hole is not a realistic solution for us, since
the
device we are making must be hermetically sealed.
Do you know of any type of no-clean flux that can maintain high
insulation
resistance at high temperatures in an enclosed space. (250 deg F)
Do you have any experience dealing with soldering practices in enclosed
spaces?

We would appreciate any suggestions or help that you may be able to
supply us
with. You can contact me. Dr. Isaak Baber at 757-426-3678.


Thank you very much,
Dr. Isaak Baber



 -----------------------------------

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