Hey everyone, just wanted to share a quick DIY hack for anyone looking to reuse their "non-refillable" Uni-ball Onyx rollerball pens.
Instead of throwing the pen away when it ran out, I managed to pull the back cap completely off the body. I filled the barrel directly with Noodler's Polar Black fountain pen ink (essentially turning it into an eyedropper pen) and popped the cap back on.
How it writes: It is working great and flows incredibly smoothly!
A couple of quick tips if you try this:
• Lubrication helps: Noodler's Polar Black is a heavily lubricated ink, which seems to keep the rollerball mechanism spinning perfectly without seizing.
• Mind the seal: Make sure your back cap snaps or presses back on tightly so air doesn't leak in and cause the tip to flood. (You can use a tiny bit of silicone grease or plumber's tape if it feels loose).
• Line width: Because Polar Black is an anti-freezing ink, it can spread a bit on cheap paper, making the line slightly wider than the factory ink, but it's completely waterproof and bulletproof now!
Highly recommend trying this before tossing your empty Onyx pens into the trash!