One of the fascinating things about a fountain pen is the way it is filled. The history of the fountain pen is mainly the history of the filling mechanism. If you’ve ever worked with ink or paint you can see why: failure of the pen, either when carrying, using, or filling, is a nasty business.
Even today there are a handful of different mechanisms on the market. Which, when you think about, tells you one thing: there’s no such thing as The Perfect Mechanism. Why is it so hard? Because some of the design criteria are at odds with each other:
- The mechanism should have a high ink capacity
- It should be reliable even after years of using it
- Refilling should not result in bringing your clothes to the drycleaner and scrubbing your hands like a surgeon
If it weren’t for the capacity, the solution would be simple: cartridges. But if you use a fountain pen, you generally use it and the pen running dry all the time becomes very, very annoying. Besides that, cartridges never offer the wide choice in ink as bottled ink does.
THe most common ways to fill a fountain pen
If it weren’t for the very limited capacity, limited choice, and relatively high price, everyone would love cartridges, because they are perfect in any other way. Maintenance becomes a matter of dunking the section in a cup of water once in a while, and that’s it.
Converter mounted on a cartridge-pen
Of course, you can use a converter. And that is almost perfect. The converter mechanism is easy to clean, and if it ever started to leak, or became stuck, it can be replaced. But the less-than-1ml ink capacity is a huge, huge turnoff for fanatic users.
This is one of the oldest mechanism. The ink is stored in a rubber or silicone bladder. By squeezing the bladder the air is pushed out, and by releasing it, its volume returns to original size, creating underpressure that is used to suck in ink through the nib.
You will hardly ever encounter these pens under that name because a myriad of mechanism to do the squeezing without removing the barrel sprung up. One of the most popular was the lever filler, where a little lever on the side of the pen was pushed out (squeezing the bladder) and released to fill up the pen.
Limited capacity and a tendency of the bladder to dry out and crack over time makes these pens a relative rare sight these days.
By far the most popular filling method of the more upscale pens is the piston filling mechanism. The reservoir is a straight tube with a piston in it. The piston is connected to a rod which in turn is connected to the knob at the end of the pen. The rod actually consists of two parts with threads; the outer part rotates with the knob, the inner part doesn’t and thus moves up and down the reservoir. From there it’s the same story: move the piston to the bottom to expell all the air, move it back up, and the resulting vacuum sucks in the ink.
The mechanism requires some maintenance (which is usually not easy to do for the owner): the piston seal requires lubrication once in a while, as does the piston mechanism. Aside from that, piston filling is nearly perfect: much larger ink capacity than cartridges, converters and sacs, and easy to fill the pen up (without having to take it apart).
The downsides: Due to the extension mechanism the piston can never travel further up the barrel than halfway. Although the ink capacity of piston fillers is in many cases respectable, it is still limited unless the barrel has astronomical proportions.
The vacuum filler has a reservoir that, like that of a piston filler, is straight, but it tapers out near the section. A thin rod connects the piston which in normal position is near the section. To fill the pen, the piston is pulled up all the way to the top of the barrel. A one-way valve releases the pressure that gets built up above the piston. Then, the piston is pushed down again, creating a vacuum behind the piston while pushing the air out of the pen in front of it. Once the piston reaches the bottom of the barrel and enters the tapered section, the vacuum is “released” and ink is sucked into the pen.
The mechanism is elegant, and unlike the piston filler, the barrel gets used almost all the way to store ink. The downside is that the main part of the reservoir has a smaller diameter (because it needs room to taper out near the section of the pen) and that the rod attached to the piston takes up (a very little) bit of space as well.
Add to it, that the mechanism is simpler to operate (no rotating parts) but requires two vacuum seals. One where the rod passes through, and the piston of course. On top of that, the piston seal needs to be constructed in such a way that it only seals off when pushed down, and not up. All that makes the vacuum filler a more expensive mechanism; its main benefit, larger capacity, can be simply offset on a piston filler by increasing the barrel size.
The oldest fill mechanism is seeing a bit of a revival: the eye-dropper. Simple screw off the barrel, and fill it with ink. The easiest way to do that without making a tremendous mess is with an eye dropper (hence the name), or a syringe.
Eye-droppers have huge capacities. But filling the pen is potentially messy, and the threads on the section need to be greased before screwing the barrel back on to prevent leaking. It’s not a miracle that other methods have sprung up over time!
Why the revival? Because a significant amount of modern fountain pen users are passionate fountain pen lovers who do not mind a little bit of inconvenience, and the eye dropper has an ink capacity that is simply unrivalled. Pens are usually not sold as eye-droppers but any cartridge-pen is a candidate.
Not every pen can be “converted” to an eye-dropper though. Ink is highly corrosive (which is why nibs are plated with corrosion resistant metals like gold or nickel) which means that metal barrels are out of the question. Also, some pens have the cap screwing on the section, not the barrel. From time to time, when you unscrew the cap, you end up unscrewing th barrel instead. Not a big deal with a cartridge pen. But with an eye-dropper…
So there you have it. Various filling mechanisms, and a reason for collectors to buy certain pens, because they want to have a pen that uses a special filling method. For daily use, piston fillers and converters are by far the most popular choice.