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We have covered these spherical ice molds before. I have used one, myself, and they work pretty well. A chunk of ice is sandwiched between two halves of a metal mold, and fast conduction of heat away from the ice, through the metal, causes it to melt wherever the mold makes contact. The mold halves slide on rods to maintain their alignment, and gravity does the rest. With a mold that starts at room temperature, it only takes a few minutes to make a nice shiny ice sphere.

This one is the work of University of Wisconsin law student Brendan O’Connor, made with tooling, technical advice, and materials from Madison hackerspace Sector67. The rods are guide rails from scrap printers. [via Hack a Day]

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.



  1. Anonymous says:

    Boiling the water before making the ice will result in better clarity.

    1. Yeah… turns out that it doesn’t work, however. You actually need to slowly agitate the ice in order to get clarity– like a waltz, not like a cellphone vibrating motor. So it’s complicated.

  2. Anonymous says:

    Nice Ice mold. Seems like not an ice.

    Nadine Thomas
    online dating profile

  3. Simon Jansen says:

    I’ve used squash balls with a slit cut in them to make round ice cubes before. They make a good spherical mould. Eventually they split though. Perhaps punching a hole at each end of the slit would prevent that?