Converting Uni-ball Air to an Eyedropper Pen

Uni-ball Air was recently introduced as a roller ball pen that mimics fountain pens in that it provides variable line widths, especially when writing Kanji characters.

It was quickly discovered that the pen comes with a cartridge, which can be filled with fountain pen inks using an eyedropper or a syringe.

Once you have used up the included cartridge, it is easy to take the Uni-ball Air apart. The cartridge comes out fairly easily with a firm pull and a slight twist. Rinse the tip and the cartridge with water until all traces of ink disappears. I didn't go thru the trouble of waiting overnight for it to air out/dry, instead just wiped it dry with a paper towel.

Below is a look at the ink delivery mechanism of the Uni-ball Air. There is nothing special to it. If you are an experienced fountain pen user, this is essentially converting the Uni-ball Air to an eyedropper pen.

Next, using a syringe or an eyedropper, fill the empty cartridge with your preferred ink. The amount of ink in the cartridge, as seen in the picture below, is 0.6ml, so I'd say to fill the cartridge you'll need 1-1.2ml of ink.

While still holding the cartridge up, cap it with the pen tip, and push the pen tip down on the cartridge firmly until you hear a click. Make sure you hear the click because only then is the cartridge properly installed and sealed.

And now you have a pressure sensitive rollerball pen filled with your favorite fountain pen ink. My plan is to buy a bunch of these, and take them on trips or to places where you're afraid your favorite fountain pen is going to get lost or damaged. Or, it is just good fun to use your fountain pen ink with a rollerball pen, once in a while.

Obviously I haven't done any long term tests to see if the fountain pen ink might dry too fast for the Uniball Air, and eventually clog up ink delivery. But at $2-$3 per pen, it's a risk worth taking in exchange for all the fun. :)