Fidget Spinner Weight Mold

After building a spinner or two I realized that I wasn't using the 22mm bearings on the spinner arms for anything more than weight. Additionally, it seemed like I could get a bit more inertia with a heavier weight. I had some Indium casting alloy around, McMaster Carr PN88635K2. It has about the same density as bronze. It melts at 117F, and so I use hot water to melt it and then I can use it for casting parts. There are different melt points available, so if you are concerned this would be exposed to temperatures higher than 117F in the wild, then maybe select a higher melt point. These alloys all contain some lead also, and I am not sure about the potential health effects from the lead in the alloy. I made some casts with this, and it worked just fine except that this metal is unique in that it expands when cooled rather than contracts. That makes it a pain to get out of the mold. I thought about adding some draft to the sides to help this, but then I don't think it would hold