How to Fill a Fountain Pen: Cartridge, Converter & Piston Step-by-Step

How to Fill a Fountain Pen: Cartridge, Converter & Piston Step-by-Step

There are three ways most people fill a fountain pen — cartridge, converter, and piston — plus two you will meet later, the eyedropper and the vacuum filler. None of them is hard once you have done it once. The single mistake that trips up beginners is not the technique; it is buying the wrong converter, because converters are not universal. Start by finding out which system your pen uses, then follow the matching steps below.

Not sure which nib and ink to fill it with in the first place? The nib finder pairs a width and an ink to how you write.

First: which system does your pen use?

• Cartridge or converter (most pens): the section unscrews from the barrel and you find either a small ink cartridge or a removable converter inside. Lamy Safari, Pilot Metropolitan, Kaweco Sport, most beginners' pens.
• Piston (built-in): there is a knob at the tail and no cartridge — the barrel itself holds the ink. TWSBI Eco, Lamy 2000, Pelikan.
• Eyedropper or vacuum: specialist high-capacity systems, covered briefly at the end.

The difference between the first two is explained in full in cartridge/converter vs piston.

Filling from a cartridge (the easiest)

1. Unscrew the barrel from the section (the grip and nib).
2. Push the cartridge onto the nipple inside the section, narrow end first, until you feel it seat with a small pop — that pop is the seal breaking.
3. Screw the barrel back on.
4. Hold the pen nib-down and wait 30–60 seconds for ink to reach the feed; a gentle squeeze of the cartridge (or a few firm shakes, cap on) speeds it up.

A note on cartridge types: proprietary cartridges (Pilot, Lamy's T10, Platinum) only fit their own brand, while standard international cartridges (short and long) fit a huge range of European and Chinese pens — Kaweco, Jinhao, Conklin and many more. If a cartridge does not seat, it is the wrong type, not a defective pen.

Filling from a converter (bottled ink on a cartridge pen)

A converter is a small refillable piston or squeeze bladder that takes a cartridge's place so you can use bottled ink. This is where fitment matters — buy the converter your pen's brand specifies:

• Pilot uses its own converters: the compact twist CON-40 for the Metropolitan, Kakuno and Prera, or the high-capacity push-button CON-70 for full-size Pilots like the Custom 74. A standard converter will not fit a Pilot.
• Lamy uses the proprietary Z28 (Safari, AL-Star, Vista) — see the Lamy Safari.
• Platinum uses its own Platinum converter.
• Kaweco Sport only fits Kaweco's short squeeze/mini converter; a standard-length converter is too long for the stubby barrel, which is why many owners eyedropper it instead.
• Standard international converters fit the pens that take standard international cartridges.

To fill, once the right converter is seated:

1. Submerge the whole nib, past the breather hole, into the ink — not just the tip.
2. Twist the converter knob all the way down, then slowly all the way up, drawing ink in (for a squeeze converter, press and release).
3. Twist the knob back a touch to expel one drop into the bottle — this clears the trapped air that causes drips and hard starts.
4. Lift out, wipe the nib and section clean on a paper towel, and reassemble.

Filling a piston pen (built-in reservoir)

Piston fillers such as the TWSBI Eco or Lamy 2000 have the mechanism built into the barrel, so there is no cartridge or converter to buy — a big reason people love them.

1. Twist the blind knob at the tail to run the piston all the way down.
2. Submerge the entire nib past the breather hole.
3. Twist the knob the other way to draw the piston up, pulling ink into the barrel.
4. Twist down slightly to expel two drops back into the bottle (clears air), then wipe the nib.

Capacity is large and you can watch the ink level through the barrel. A bottle of Diamine or an ink sample set is the natural companion.

Eyedropper and vacuum (the high-capacity outliers)

• Eyedropper: the barrel is the tank. Grease the section threads with a thin film of silicone grease, use a syringe or pipette to fill the barrel with ink, and screw the section on. Enormous capacity; be aware it can "burp" a drop as it empties and warms in the hand. The Platinum Preppy is the classic first eyedropper hack.
• Vacuum filler: on pens like the Pilot Custom 823, unscrew the blind cap, submerge the nib, and push the plunger down in one firm stroke — a vacuum yanks a barrel-full of ink in at once.

Common filling mistakes

• Dipping only the tip. The feed fills through the breather hole; submerge the whole nib or you will draw mostly air.
• The wrong converter. Covered above — match the brand, not the look.
• Skipping the expel-a-drop step. Trapped air burps ink onto the page and causes hard starts.
• A half-seated cartridge. Push until it pops, or ink never flows.

Once filled, cap the pen, prime it with a couple of strokes on scrap paper, and write. If it hard-starts or drops strokes, that is a flow issue, not a fill issue — the fixes are in how to stop skipping and hard starts. And before you change to a different ink color, give it a rinse first: how to clean a fountain pen. More pens to fill are ranked at the /best hub.