Hold More Ink in Your Cartridge Fountain Pen

This pen uses the shorter Universal or Mont Blanc cartridge shown on the right. It would be very handy if I could travel with a bigger cartridge in the pen that would hold more ink.

The cartridges on the right are the Mont Blanc style cartridge used by many fountain pens. The cartridge on the left is a Waterman cartridge. The fitting where the cartridge attaches to the pen's nib section is identical on both the Mont Blanc and the Waterman cartridges.

Waterman cartridges are usually too long to fit into a pen designed for Mont Blanc cartridges, even if the barrel of the pen is made to accept an extra Mont Blanc cartridge inverted for storage. This pen came with an extra Mont Blanc cartridge stored inverted behind the working cartridge, but I cannot get a new Mont Blanc cartridge to go far enough into the barrel for the nib section to screw into the pen. Even if it did fit, I would like to avoid changing cartridges, especially while I am at a meeting out of town.

Cut about 3/8 inch (10 mm) from the back end of a Waterman cartridge. Before cutting I used an eyedropper with a piece of hobby tubing glued into its end to remove the ink in the cartridge. See my earlier Instructable: https://www.instructables.com/id/Refill_Your_Fountain_Pen_Cartridges_and_Save/

A plug made from hot glue will seal the end of the cartridge. To be certain the plug will not come out of the end of the cartridge, I drilled a hole through the sides of the cartridge as shown. Trim any shards of plastic to make nice clean holes. Clean away any ink from the inside of the cartridge end with the twisted corner of a facial tissue.

Put just a very little hot glue into the end of the cartridge. Dap a little into each of the holes in the side of the cartridge. This will make wings that lock the plug into the cartridge when the glue has cooled. Notice the lump of hot glue that extends from the plug through the hole on the side of the cartridge. When the glue has hardened, trim the lumps of glue away so the outside of the cartridge is smooth. Use a little sandpaper, too.

You now have a much larger cartridge to hold much more ink. Check to be certain the cartridge does not stick inside the pen's barrel when you unscrew the nib section. If it does, you may need to shorten your new longer cartridge just a little.

If you notice any signs of leakage around the hot glue plug, remove the ink from the cartridge. Push some shreds of paraffin into the cartridge, and play on the cartridge with a hair dryer to melt the paraffin while holding the plugged end of the cartridge down.

Sometimes the ink goes to the end of the cartridge and stays there by a capillary action. Something to break the surface tension is needed to get the ink to flow down to the nib end of the cartridge when you begin to write. I cut a piece of #12 gauge copper wire about 3/16 of an inch long and inserted it into the cartridge. It generally does the trick very nicely. Steel might rust, but stainless steel would be good.