For those unfamiliar with it, Bocce Ball is an outdoor game played with a set of heavy grapefruit-sized balls. We’ve never really thought of making our own set, but as you can see above, it can be done. These are six Bocce balls produced at home by [Horvitz444].
It seems the commercially available balls have a cement or clay core covered in a layer of high-impact epoxy. [Horvitz444] was able to recreate this starting with some vacuum forming. He built his own former out of peg board and a shop vac. The plastic stock he used was a light panel from the home store. After heating it up in the oven he formed a mold using what looks like two halves of Bocce balls. The mold halves were melted together using a soldering iron. After pouring in the secret concoction of cement ingredients and letting them harden, he removed the orbs from the molds and ground down the seams until smooth. They were covered in epoxy and painted. Most of these details were gleaned from his comments in the Reddit thread.