Premature latex sac failure and ammonia

For quite a few years now pen collectors have been trying to determine why latex rubber ink sacs fail -- and in particular, why they sometimes fail so quickly. Certain inks have been implicated, and yet efforts to conduct controlled experiments have for the most part not succeeded in producing consistent results and clear conclusions (the exception being highly alkaline inks, which have long been known to attack sacs).

Some time ago I asked my old friend Peter Amis, longtime proprietor of the Pen Sac Company, if he could provide any insight into why newly-made sacs didn't seem to be holding up as well as those made in the 1950s and 1960s, but I never got a clear answer. Peter recently passed away, far too soon -- a huge loss to the pen community. During Peter's illness, Todd Eberspacher stepped in to help keep the Pen Sac Company going, eventually leading to an agreement to take the business over. 

Todd has shared with me much about what he has had to learn about the making of pen sacs. It turns out that environmental and workplace safety issues have led to major changes in how latex pen sacs are made, with the toxic solvents used in the past replaced by water-based solutions. This has affected durability in much the same way as the switch from oil-based to latex house paints. And the new formulations are in part activated by ammonia -- which I am told makes them particularly vulnerable to subsequent ammonia exposure.

The risks ammonia poses to gold nibs has already been documented at length here. That it is also bad for sacs has not been noted previously but should now be accepted as fact. Ammonia-containing pen flush products should not be used on either gold nibs or in pens with latex rubber sacs, including Vacumatic diaphragms.