This pen came to me again to restore the filling mechanism. On unscrewing the knob from the end of the barrel, this revealed a plastic bulb (quite like the glass cartridge on the Waterman Jif). However, when unscrewing the barrel it revealed a very different mechanism.

Inside was a very rotted “accordion” sac. A thin hollow plastic tube runs from the feed through the sac and into the top of the plastic bulb. The filling mechanism operates simply by pressing the end of the bulb, which compresses the accordion sac, expelling the air and then when released, the resultant vacuum sucks ink into the sac and bulb.

The question was, how to replace a rotted accordion sac. Initially I tried using a standard sac by cutting to the required length and cutting off the bottom. This kind of worked when tested outside of the pen, but when put back into the barrel, the sac bulged and kept sticking to the inside of the barrel. The only other solution was to see if anyone had a replacement accordion sac, and lo and behold, after a few minutes searching, I found that my usual supplier of sacs (vintagepensacsandparts.com aka Pendragons) had just recently got hold of a few NOS accordion sacs. I quickly ordered a couple of each size and 2 days later I had a perfect replacement.

Once the sac had been measured (by laying out the components aligned with the barrel, feed and knob, I cut that to size and fitted one end over the section nipple, and the other end over the plastic bulb. I then reassembled the pen ready to test and send back to its owner. It’s always a pleasure to bring these old writing instruments back to life.