Kaweco Sport Eyedropper Conversion – A How-To

One of the best features of the Kaweco Sport is that you can easily and quickly turn it into an eyedropper – enabling you to hold a ton of ink, and if you’re using the clear demonstrator, have a moving air bubble in a tube of ink to keep you entertained during long meetings.

Kaweco takes international short cartridges and has its own brand of cartridges, each holding around 0.5 mL. A eyedropper Kaweco can hold about 2 mL.

You will need:

Kaweco Sport Pen
100% Pure Silicone Grease
Syringe or Eyedropper
Bottle of Ink 

The silicone grease is to prevent any leaks. You can buy silicone grease at some plumbing or hardware stores, other pen supply stores, and most (if not all?) diving/scuba stores. We went to Home Depot, and only found some “plumber’s grease” which appeared to be at least mostly silicone grease, but we weren’t sure if it was 100% pure – which is the safest to guard against any ink reactions. You can also purchase from us here. One jar or tube of silicone grease will last you quite a while.

The syringe, for getting ink from the bottle to the pen, you can get from a pharmacy. We offer blunt tip, reusable needles here.

In this post, we’re converting a Kaweco Sport Demonstrator Fountain Pen, but you can also do this with a Preppy, or find tips here for your Serwex 101, which is already an eyedropper. You should not turn your Kaweco Al-Sport into an eyedropper, since it’s made out of aluminum, which can react with the ink.

The ink we’re using is Noodler’s Tiananmen Square.

The Kaweco Sport Fountain Pen comes with a cartridge in the pen barrel, which you won’t need.

Dip your finger in to get some of the silicone grease.

Spread evenly and thinly around the threads of the nib section.

The silicone grease should be applied to the threads of the nib section. You don’t need a huge amount, but make sure you cover the threads evenly so ink can’t leak out.

Draw up ink from the bottle with the syringe. A Kaweco Eyedropper can hold about 2mL.

You can fill up the pen barrel up to the inner threads (the lower ones) so ink doesn’t spill out when you insert the nib section.

After you’ve filled up the barrel, you can twist in the nib section. Be careful to keep the pen barrel up so you don’t spill!

Wipe off any excess silicone grease that squeezed through the threads.

You are good to go! Turn it nib down so the ink can begin to make its way through the feed. 

For the most part, while eyedroppers are more prone to leaks than, for example, cartridge/converter pens, you shouldn’t get a leak if you have sealed it properly and aren’t doing crazy things with it.

Some eyedroppers can tend to “blob” out ink from the nib when the barrel is almost empty, due to changes in the air pressure and the capillary action of the feed.

As well, when you have a lot of air in the barrel (2/3 air, 1/3 ink), and you warm up the barrel too much with your hands or in a shirt pocket, you might also start to get blobs. The increase in pressure due to the warming of the air can force droplets of ink out.  If you’re someone who grips the pen tightly or for long periods of time, warming up the air in the barrel, you may also want to considering making sure your pen is refilled with ink when it nears the halfway point.

Each time you unscrew and screw the section and barrel to refill the ink, you may squeeze out a bit of the silicone grease, so I would recommend refreshing the silicone grease every once in a while, especially if you’re cleaning out the pen to change ink colours.