Customizable hexagonal dumbbell molds

These are customizable molds for concrete dumbbells. They include a guide for the rod too be glued inside (I used a wooden rod). I printed mine thin (1.2mm) and then they peeled off the concrete (except near the guide at the bottom). If you print yours thick enough, you should be able to get plastic-encased weights.

The default is for 33.5mm rod and 25 lb dumbbells.

Build instructions are here.