If I haven't let on to this, I really like Parkers, and expecially vintage Parkers, a lot. It's my second favorite brand next to Montblanc, and at the moment actually outnumbers MB in my collection(that will change with a few planned MB purchases...)
In any case, a few posts ago I talked about the Duofold, and specifically my modern "Big Red."
I've wanted an original "Big Red", but they can be fairly valuable. I'd really like a hard rubber one, but they're difficult to even find in passable condition.
Earlier this week, though, I did a bit of dealing on Ebay and managed to get a celluloid "flat top" one(same size/profile as the hard rubber ones) for a reasonable price.
It was really nice cosmetically, but was sold as an estate find and "might need a new ink sac." I've actually never sacced a pen, but have enough that need it and I hate paying ~$50+3 month turn around for what is honestly a fairly straight forward repair.
To expound on that a bit, virtually all self-filling pens(those with a built in filling mechanism) today are piston fillers-a piston moves inside the barrel to draw ink in(see the 149 above). Most converters for cartridge pens also work this way. A small number use a really neat system called a vacuum filler, which works by pushing down a plunger that creates a vacuum in the barrel then "releases" it to allow the nib to soak up ink.
Most of the early self filling pens, though, were what I generically call "sac filling pens." Basically they have a latex rubber sac that is compressed by a pressure bar, expelling air, then released and allowed to suck up ink. The single most common arrangement was a lever set into the side of the pen to press the pressure bar, although there were other arrangements like the button fillers that Parker mostly used. These had a "button" under the blind cap that was pressed to activate the pressure bar. Later, Parker came out with a PVC sac that was filled by pressing directly on the pressure bar-this is called the Aeromatic filler, and is a virtually bulletproof filling system that first was used on Parker 51s and later several other models.
In any case, though, I received the "Big Red", and sure enough it showed no evidence of a functional sac. With that said, often the sac will have petrified, broken up, and can be heard rattling around in the barrel.
Finally, I braved it, opened it up, and saw something interesting. There was what appeared to be a new sac on the pen, but there was also a hole in the side of it
One of George Parker's early claims to fame was something called the "Lucky Curve" feed, which helped prevent the pen from "burping." The earlier Duofolds had it(unless they've been cut off or broken) and the "lucky curve" was what was poking out the ink sac
So, I've ordered some sacs and I'll be attempting this one as my first replacement...
