Converting fountain pens into an eyedropper-fill pen
Some acrylic resin fountain pens are capable of being converted from a cartridge/converter to an eyedropper-fill fountain pen. A pocket pen like the Kaweco Sport, for example, only accepts an international ink cartridge or the Sport piston converter, which does not contain much ink. If the pen is converted into an eyedropper, the ink capacity is multiplied.
We caution to say that not all cartridge/converter fountain pens can be converted to eyedropper. How to find a good candidate for eyedropper conversion? First, check the inside of the pen barrel and the section threads that attach to the barrel. If there is any metal that would come in contact with the ink, then you can't eyedropper convert it. Most likely, the metal will corrode due to constant ink exposure. Second, you would have to test the barrel to see if it can hold water. Some pen barrels are made in separate parts. They may have a finial that is not completely watertight. Fill the pen up with water and let it sit for a day on a paper towel. If you see leakage, it's a no-go. To verify your own findings, look up your particular pen model and the words "eyedropper conversion" on google to read up on the trials of fellow pen enthusiasts before you.
The key to eyedroppering a fountain pen is using 100% silicone grease. The section threads need a little coating of this grease to create a watertight seal where the section attaches to the barrel. When writing with an eyedroppered pen, be mindful of any drastic changes to air pressure or temperature, especially as the ink level drops below half the total volume of the barrel. Such atmospheric changes can cause air to expand inside the barrel and force out ink through the nib, causing a "burp" of ink on the page as you write.
Other (Vintage) Filling Systems
While the aforementioned methods are the most common filling systems you will find on modern fountain pens, you may stumble across unusual types in vintage pens, such as lever, crescent, vacumatic, safety, snorkel, aerometric, touchdown, and so on. Each has its own unique design, filling instructions, benefits, and drawbacks. If you're interested in vintage fountain pens, we suggest looking for them at a pen show. Talk to the dealer to find out more information about the pen and its filling system.
The type of filling system that best suits you is a decision that weighs convenience versus ink capacity. If you want a high ink capacity and don't switch colors often, then a piston, vac or eyedropper will work well for your writing habits. A writer that lives out of their suitcase might find cartridges more convenient than carrying glass bottles of ink. If you change colors often and have 10 to 20 pens inked at one time, you may like the option of a cartridge converter so your pens do not sit with a full barrel of ink for months at a time.
Filling a fountain pen should not be a hassle. It's one of the fun aspects of owning a refillable writing instrument that will last you decades instead of being thrown in the trash when it runs dry. We hope the information in this article helped you fill your fountain pen or find a filling system that meets your writing preferences. If you have any questions, please feel free to contact us and we'll be glad to help.