It's a known fact that larger pieces of ice last longer than smaller pieces. I for one like ice in my bourbon and after reading that the ideal way to make ice for bourbon (and other drinks) is a large ball shape. Well, here is a large 60mm ice ball mold. While this is only for a single ice ball, the TPU molds can be duplicated and you can create a mold for as many ice balls as you wish. This was created more as a proof of concept rather than as the final design. The most important component here is the upper and lower TPU molds.

The two clamps perfectly align the upper and lower TPU molds with matching grooves for the TPU shells. The upper and lower clamps are held together with ¼-20 hardware. One half of the clamp contains the mating threads for this hardware but you can use whatever you have on hand.

The upper and lower TPU molds are essentially the same with the top one containing a fill hole and small funnel shape. Filling can be a bit of a challenge, but there are a number of simple ways to fill the mold. I simply held the assembled mold under water and simply “pumped” the TPU mold until all of the air was evacuated. 

What I used: 

I used the following for the TPU parts:

• Overture TPU - White - Print slowly for best results
• 20% infill / gyroid pattern
• .4mm nozzle
• .2mm layer height
• 3 layers top and bottom
• 2 perimeters
• internal supports for the upper portion of the spheres

I used the following for the PLA parts:

• 4mm Nozzle
• .2mm layer height
• 4 layer top and bottom
• 4 perimeters
• 100% infill