In one method he uses a silicone mold to make a clear ice ball. Note that these molds are also available for making four, six and 25 ice balls, so this may be a

In one method he uses a silicone mold to make a clear ice ball. Note that these molds are also available for making four, six and 25 ice balls, so this may be a more efficient method than it looks, and no wire should be required.