After reading the post on what type of talc to use, I started wondering just how necessary it is? I assume that it's purpose is to reduce the friction between the bar and the sac and to keep the sac from sticking to the barrel after it's been compressed. Is it necessary or just a precaution? Will a pen that functions perfect now fail in 1 year... 5 years... who knows how long? What if I decide to never use it? Give me a clue here...

Given the fact that there are working Esties with 50- and 60-year old sacs, I think you might make it five years with no talc.

That was kind of a joke. I think that talc might be totally unnecessary. However, for me, if I am going to order sacs, I might as well order talc.

The thing is, if I ever sell a pen, and say that I re-sacced it, best practices necessitates the talc, and buyers should have confidence that I did the job right.

For a standard sac type of pen you can get away without it, but it does help the sac to slide down the barrel when the pressure bar is touching it. It can also help to keep the sac from sticking to the pressure bar and barrel wall when it starts to break down.

But with a Vacumatic type of filler it is absolutely essential. You need a dry lubricant on the sac so that it doesn't stick to itself and bind up as you fill the pen. Talc is the easiest to find. Graphite would work but it's really messy.

By the way, you should NEVER use silicone grease on the inside (folded in part) of a vac diaphragm. I've had to repair many pens where this was done. Every one of them failed because the rubber and silicone balled up and the diaphragm bound up.

It seems essential for a button filler, but that is just my observation after re-sacing a number of them. Button fillers are usually a tight fit, and the talc prevents the sac from twisting up when I screw the barrel back on.

Andrew

Ah, there's your problem!! When repairing a button filler, you should remove the button and the pressure bar, then unscrew the section to prevent damage to the pen. When you reassemble, screw the section into the barrel, and then insert the pressure bar and button. Make the sac just a tad short so that the pressure bar can be slipped easily between the sac and barrel wall. Make sure you have it turned the right way too.