How to convert a fountain pen to fill by eyedropperUpdated 10 months ago

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 eyedropper-converting 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.