Pens and Pencils | Reviews and Data

How To Fill A Fountain Pen

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Fountain pens tend to seem relatively self-explanatory, but that doesn’t mean the correct process for filling every pen is obvious. This article will out how to fill any common fountain pen we’ve encountered.

If you need some more explanation about the different types of fountain pen filling systems, check out our guide.

Universal Rules

Despite all the different types of fountain pen filling, there are some rules that always apply!

One important rule is to fully submerge the pen nib when filling it. Fountain pens have a nib and a breather hole, the latter of which isn’t usually very obvious when looking at the pen, but it’s where most of the ink will enter some pens when filling them. As a result, a pen won’t fill unless both of these things are fully submerged in your ink bottle.

Piston Fountain Pens

A piston-filling fountain pen has a piston — just like in a car — inside the barrel. This piston goes down to expel air or ink and then back up, pulling ink into the barrel.

The typical process is very simple, assuming the pen is clean and dry:

  1. Push the piston down, expelling any air in the barrel
  2. Submerge the nib, ideally up to the lower grip
  3. Turn the barrel and pull in the ink
  4. Turn the piston it’s open-most point, lock if possible

Twsbi Eco

How to fill a Tswbi Eco

Like most piston-fillers the Twsbi Eco has a knob on the top that turns to have the piston go up or down.

Twsbi Go

The Twsbi Go has a piston-filler that is spring-loaded, instead of twisting to go up and down. It’s fundamentally the same concept, but the push-button spring mechanism gives you less fine control of the fill.


A cartridge-converter is a fountain pen that takes a cartridge or a fountain pen converter, like Pilot’s CON-40. A converter is a device that attaches to a fountain pen, bringing the filling mechanism with it. The mechanism can be a piston, a squeeze sac, or any other number of fill types.

Pilot Metropolitan

How to fill a Pilot CON-40

The Pilot Metropolitan is a cartridge-converter fountain pen that usually uses Pilot’s disposable cartridges.

Working with a fountain pen cartridge is very easy. You simply open the pen, then get the cartridge and push it into the little stem on the inside of the fountain pen, at the top of the grip piece. There will be a firm click and you’ll notice that the cartridge is firmly stuck onto the grip piece, with no wiggle. The ink will start flowing on its own and soon the pen will be writing.

The number one thing to keep in mind is that not all fountain pens and cartridges are compatible. This fountain pen cartridge guide will help!

If you opt for a converter then you simply open the pen, then get the converter and push it into the pen firmly. Just like with a cartridge you’ll need to make sure the pen and converter are compatible!

Since there are all sorts of converters, you’ll have to figure out the type you have (or even the specific model) before you know how to fill in. Here are some popular options:


An aerometric filler is a rubber sac. Using it is very simple: open the pen, submerge the nib and breather hole, squeeze the sac or spring around the sac expelling the air inside, and then let go, all the rubber to go back into its original shape and pulling in ink.

A rubber sac or aerometric filler is the simplest mechanism in any fountain pen, short of an eyedropper — which has no mechanism at all! This method was very popular, having been found on pens like the Parker 51 and Aurora Hastil, but isn’t as popular these days.

Vacuum Filler

Vacuum-filling fountain pens might seem like magic, but they are very simple to use in practice. You simply need to:

  • unscrew the top of the pen
  • pull the top of the pen out all the way
  • submerge the nib and breather hole entirely
  • push the top of the pen down until there is a pop sounds or similar break in pressure
  • you will see the ink flowing in the pen and up the barrel as the vacuum area you created by pushing the top down is filled with ink

Note: This article is a work in progress and will expand as we get access to more pen documentation! Feel free to email if you have any you’d like to share.