I work in cocktail bars and run cocktail events. When I don't have access to a clinebell, I make my own using a similar setup, but it only costs about $5.

Buy a largish tupperware container, say 2-5 gallons, and wrap the sides and top--not the bottom--in insulating foam. Fill with purified water and place in a conventional freezer for at least 12 hours for smaller containers, 24+ for larger ones.

The idea is that the bottom will chill faster while the air bubbles rise to concentrate the cloudiness at the top. You'll wind up with a nice block that's mostly clear, save for an inch or so at the top.

Tips:

* Remove all food products and put baking soda in the freezer. You don't want your ice to taste like fish sticks.

* When you cut the ice, leave it out at room temperature for ~10 minutes before cutting. Score lines in the block use a mallet and knife edge to separate pieces.