I posted this question in another thread that seems to have died, so I repeat it here.
I have a desk pen in teal that I acquired from the previous user of my desk in grad school. That was about 50 years ago, and it has always been somewhere on a shelf or on a desk, but it always seems to dry out very quickly. Is there a trick to keeping them inked? Is it the choice of ink, or perhaps how well it fits in the holder socket?
How fast is "seems to dry out very quickly?"
If you leave the pen for a week or two, the ink will evaporate from the pen, and will dry out.
Many bases do not have a snug fitting holder. So when not used for a day or so, the water in the ink ink in the feed will evaporate, leaving a concentrated ink that will not flow very well. A quick dip in water (just half the nib, in and quickly out) is usually enough to rehydrate the ink in the feed.
If the pen is 50 years old and has not had the ink sac replaced in the last 10 years, my guess is that the ink sac has failed and you only have ink in the feed of the pen. That is would explain why the pen is drying out fast. The pen is not able to store any more ink than what the feed will hold. BTW, ink sacs have a finite life.