Perfectly clear ice spheres are nifty but can be a bit tricky to make without an apparatus ... and in this case we get to see 3d printing, sand casting, lost PLA casting, lathe turning, milling ...

The print is carefully sanded down and post-processed to be highly smooth, so that it doesn’t spoil the mold when its removed for the casting process. From there, a sand casting mold is built ...

Such pots were very complex to make. Being able to produce one meant ... Abraham Darby I patented his method of sand casting iron pots using re-usable patterns in 1707 and laid the foundation ...