Day Two

Essentially, there are two problems I have to overcome to get a ‘zero-gravity’ ball-point pen to work. I have to find a suitable “ball”, and something it can sit in such that it’s held firmly in place while being free to ‘roll’. Then there’s the question of how to deliver just the right amount of ink to the ball in order for it to write evenly and continuously…and upside down! A spring-loaded marble inside a piece of copper tubing containing some ink, with an inflated balloon providing the pressure to force the ink onto the marble seems to work – provided the ink is sufficiently viscous.

All the designs I've tried for these pens are far from ideal, but at least the two I end up with are functioning pens that will write 'upside down'. Tomorrow, I’ll aim to scale down both the capillary-action and ball-point designs and try to get them to work more effectively.