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 ex