I was fixing the other day another VacFill and I found that I had only one of David Nishimura's packing gaskets left (By the way, Dave, if you are there, let me know if you received my June 1st order). And just in the same box, I had a lot of Giovanni's Snorkel point seals, which looked exactly the same as the VacFill gasket. So I went and use an snork seal and (rattling of drums) it is a perfect fit. When pushed down, the plunger comes back 100%, so the vacuum it creates is good.
My question. Giovanni offers the gasket in three flavours: Nitrile, Ethylene-Propylene and Fluorocarbon. Which one will resist best permanent contact with ink?