Lily Yeazell

this week I decided to make this shape called a reuleaux tetrahedron. It's the 3D analog to a 2D shape called the reuleaux triangle, which is a shape with equal width. Similarly, the tetrahedron version also has essentially equal width throughout the surface. This property is cool because it means it can roll like a circle or sphere.

In terms of constructing this shape it is the intersection of 4 spheres, which is not difficult to do in CAD, so I used fusion 360 to make it

I originally thought about splitting the shape in half to make a 2 part mold, but I didn't like the idea of the parting line down the middle, so I came up with a more complicated mold where one piece would fit within the other, and the parting line would be along the curved edges

I used the CNC router to mill a rigid mold from a 7"x3"x1.5" wax block.

Then I poured silicone into it to create a flexible mold.

pouring the hydrostone was actually more difficult than I expected. At first the mixture I had was too thick for the size of a hole I had cut. A bubble ended up getting trapped and left a weird dimple on the shape. my second attempt was better but there were still some small air bubbles.

It kinda rolls!