I really like Kaweco Liliput pocket pens – they are simple, robust and beautifully machined fountain pens. However, the Liliput’s small size mandates that ink cartridges need to used instead of a cartridge converter. I became frustrated with what I perceived as ink starvation when writing for extended periods of time with the pen, so I decided to look into this phenomenon in more detail.
The picture below shows a cross-section view of the interface between the ink cartridge and the Kaweco (Bock) 060 nib. This 060 nib is used on all Kaweco fountain pens, except the Elite and Supra models. It shows that the plastic ball that originally sealed the ink cartridge sits nicely on top of the feed tube when the pen is orientated upright – which is the opposite of what’s desirable from an ink flow perspective.
The feed tube length for the Kaweco (Bock) 250 nib (used on the Elite and Supra pens) extends about twice as far into the ink cartridge, so the mechanism for the plastic ball to obstruct the feed tube is largely mitigated for this design.
My solution to this perceived problem is to prevent the plastic ball from being pushed into the cartridge. I use crimp pliers (i.e. smooth jaws) to squeeze the cartridge and eject the plastic ball from a new ink cartridge. Its a bit messy, but only needs to done when a replacement cartridge is required. I empty the cartridge and dry it out – then fill it with my favorite (Monblanc permanent blue) ink using a 0.2ml disposable transfer pipette. A photo of a (truly) empty ink cartridge and pipette is shown below. The 0.2ml pipette is small enough to be inserted into the ink cartridge, and represents a very compact and inexpensive approach to fill cartridges. I reuse the pipettes numerous times, so I have a lifetime supply from the minimum quantity of 200 that I bought from Amazon for about $20.
If you find that you’ve experienced similar ink flow problems with your Kaweco cartridge pens, you may wish to consider the above approach to hacking the Kaweco cartridge interface.