Katharine Gammon writes in Wired about the work of McGill University researcher Pieter Sijpkes and colleagues, who have produced an experimental 3D printer that produces ice-sculptures. The researchers give current applications as a cheap alternative to printing in plastic goop (thanks to patents that will soon expire, the plastic powder used in high-end 3D printers costs more than filet mignon) and for "ice tourism."
He and his team have printed a statue, an egg carton, a martini glass, and molds that melt conveniently away. Why ice? Well, it's cheap and readily available, and low-cost ice models could help inventors design products more quickly. The challenge of printing with ice, besides the very cold temps necessary for the process, was building a machine that's up to the task. Here's how Sijpkes did it.
Building a 3-D Printer for Supercool Ice Objects