Step 1) Put the cartridge on some paper towels in an area where you can tolerate a spill.
Step 2) Turn the cartridge upside down.
Step 3) Remove the black dimple plug over the fill hole. You may need to scrape it off with a knife or screwdriver.
Step 4) Push the ball in the fill hole into the cartridge with a ball point pen or similar device. Forget about it.
Step 5) Inject 30 ml of the ink into the fill hole slowly. You may add an additional 5 ml if the cartridge will take it. Fill to the bottom of the fill hole.
Step 6) Now you must seal the fill hole air tight. We suggest using silicon rubber, hot glue, or (preferred) a 10-32 x 1/2 inch long (M6) set screw. (Stainless steel is preferred for longer life, but regular steel will do.
Whichever you decide to use, you should squeeze and hold the cartridge just before sealing to set up the vacuum. Make sure the seal is flush or just below the cartridge surface.
Step 7) After sealing, release the sides of the cartridge and squeeze again, twice. A couple of drops of ink should come out of the printhead.
Step 8) You might wish to set the cartridge over a paper towel for an hour as a drip precaution. Expect a few drips until the vacuum stabilizes. Before inserting the cartridge, blot off the hanging drop of ink with a paper towel.
Step 9) When inserting the cartridge, first tilt the cartridge so that the ball is caught above the set screw and doesn't roll into the area above the print head, where it can occasionally block off some ink flow.