I found a plastic sign in my basement last night, originally I wanted to keep it for what it was ( caution: keep hands away from moving machinery ) but apparently it had been leaned up against my furnace vent and kinda molded to it, whoops. Anyway, the plastic is just about the right thickness, im going to experiment with it. I want to think of a way i can heat up the bottom edge, and roll it into shape for the paper clip section.
Paint - how did you keep the clip piece in the cover? does the pen spring have just enough tension to hold it in place or did you capture it with something