In the number of ways on how you can fill and store a fountain pen with ink, cartridges and converters are the common and popular systems. It ease of replacement, simplicity in operation and cleaning, and compatibility among other pen brands (except for those who has a proprietary design), these filling systems are widely used in fountain pens. The downside of these filling systems with other forms is the ink capacity. Cartridges and converters are limited because they are confined to the size of the container, unlike a vacuum, piston, or eyedropper which takes advantage of the barrel as its container. Converters are cartridges with an added feature of refillability; this means that unlike a cartridge, converters can be cleaned or refilled by the same ink without its removal from the pen.
The number of fountain pen brands, that uses cartridges and converters, either fall into two categories: those who follow the specifications of the standard international, and those who follow their own proprietary design. This entry would focus on the proprietary categories, in particular, Pilot pens cartridges and converters, sharing my thoughts on their compatibility on across their pen portfolios, and the idea of their cartridges as reusable and resealable compared to other manufacturers.
Pilot cartridges come in two kinds. The first is the standard size (the two from the right) which is used in almost all of Pilot's fountain pen portfolio, including the Pilot Parallel. The second (the one on the left) is made especially for the Pilot Petit line of pens. The Petit cartridges have two small tabs which aid in the alignment of a collar, when it is placed in the pen. With a small modification on the Petit cartridges, one can take an x-acto knife and gently trim the tabs to have it compatible in any regular sized Pilot fountain pens. One of the feature that I want to highlight with Pilot's cartridges is the ability to refill an empty cartridges and reseal it with the same plug it came.
In these sets of images, it can be seen that by taking the seal out of the cartridge using some tweezers, the seal can be cleaned, reset the seal flushed with the cartridge, and using a plastic rod ram the seal down with even pressure. The one I used in this photo is the standard size that can be also done in the Petit size. When ramming the seal down, it is best to position the rod at the center and apply even pressure to the seal. When refilling the cartridge with ink, fill it below the smooth part of the cartridge, this will prevent the ink from shooting up in case you need to redo the sealing.
The seal, as shown in the image above, should not be too deep inside the cartridge nor should it be too shallow that upon puncture, the ink will spill inside the section. I found this feature with Pilot's cartridges as a thoughtful decision on their design. This gives individuals some options. Those who enjoy Pilot fountain pens but have a particular ink they wanted to use, maybe an ink who is known to leave a permanent stain and does not want their precious CON-70 to be destroyed.
I have used this system during examinations, and I usually prepare by these two principles: first is, carry two pens that you are comfortable on writing, on the idea that one is none, two is one; and the second is always prepare for the worst. In our exams, I already know what is the quality of paper in our booklets, so I typically use a Metropolitan and a Kakuno, both in fine nibs, and J. Herbin Perle Noire as ink. These two fountain pens have been reliable and I am comfortable using them during exams. Instead of using a converter and bringing along a bottle of ink, I use cartridges filled with Perle Noire. I do not have to worry that when either pens ran out or one suddenly stopped working, I can easily diagnose the problem.
This kind of feature of resealable and reuse is absent on cartridges of other manufacturers. It can be that this is a marketing strategy of some brands to entice people to buy more. I would prefer a brand who offers cartridges which can be securely resealed and be reused for another time. The ability to refill a cartridge and reseal it, to have a back up in case of emergency, is a great thing. In addition, probably saving the whales from extra plastic in the sea.
Another feature of Pilot's cartridges and converters are its compatibility on almost all of its pen portfolio. Whether it be cartridges or converters and as long as the barrel can accommodate it, all of Pilot's pens which accepts cartridges and converters are compatible. This is primarily due of Pilot's proprietary design; a design which can be seen even in their vintage pens.
The photo on the left is the part in the section that connects to either a cartridge or a converter taken from a Pilot Pocket made in the 1970's, and on the right is the section of a Pilot Kakuno. Both of these pens are from two different times in Pilot's manufacturing, and with the succeeding pictures, it can be seen that there is consistency in their design.
The photo above is a CON-70, Pilot's push button vacuum converter. It can be seen that both in the vintage and the modern Pilot fountain pen it can be compatible in its use.
It can also be seen with a CON-50 on the left, and a CON-40 on the right.
Similarly, with the CON-20 on the left, and the CON-W on the right.
While some of the pen manufacturers have the same proprietary design in their cartridges and converters, such as Parker, Lamy, Sailor, and Platinum, when it comes the variety of cartridges, number of pen options ideal for your budget, and its re usability, Pilot takes the cake on such idea. Pilot has made it accessible and more "environment friendly" the use of fountain pens, while retaining the quality and consistency in all their product lines.
At the end of the day, the only objection I have with Pilot is the standard issue of the CON-W on some of their entry level pens. When you purchase either a Metropolitan, a Birdie, or a 78G, the standard issue converter is a CON-W. In my opinion, aerometric converters are the worst converters, and it does not look great with demonstrator pens. The protruding latex is like a condom is holding your ink and you cannot really see the ink level, unlike the CON-40 or 50. They should have stopped production of the CON-W and 20 than the 50.