The temp gauges do use Diethyl ether. If you've ever broke
loose the temp bulb and noticed that sweet starter fluid smell
then you probably popped the seal. Ether's boiling point is
94.28°F and it doesn't need to boil to evaporate.
You can split the tube to the temp gauge, vacuum leak check
both ends and seal the leak. Then recharge the bulb, Keeping
it submerged in a bucket of ice will slow the evaporation
while you splice the tube. The question is, how much ether do
you charge it with to maintain the calibration?
The Ranco sensor is not filled with any liquid, it's simply a
sealed system made up of a diaphragm and tube. It's basically
just a simple type of barometer. It has to be vacuum tight
and the only way you could check it would be to split the
tube, vacuum or pressure test the two ends for leaks, patch
the leaks and then splice the tube. Having done High vacuum
leak testing on liquid nitrogen and liquid Helium systems
for many years I would guess that the weak spot would be
the diaphragm, which would be pretty tricky to patch.
Finding the right sized tube to use as a splice would be
another stumbling block and fabricating one from a rod would
probably be your best bet. And lastly, I'm not sure how you
would keep the air inside from collapsing the diaphragm as it
cooled after the splice was heated. I think during manufacture
the system was sealed at the very tip, very rapidly. putting
a heat sink near the end while you rapidly soldered it closed
might work.
If I didn't have a thousand things on the list that were more
important, I might try restoring either one of these. Maybe
if I live long enough I'll get down to the bottom of the list.
dg
Last edited by Denny Graham; 10/20/2015 9:54 AM.
