Researchers from North Carolina State University (NCSU) have developed a 3D printer capable of building with liquid metal at room temperature.

"It's difficult to create structures out of liquids, because liquids want to bead up. But we've found that a liquid metal alloy of gallium and indium reacts to the oxygen in the air at room temperature to form a 'skin' that allows the liquid metal structures to retain their shapes," says Dr. Michael Dickey, assistant professor of chemical and biomolecular engineering at NC State.

The NCSU researchers have developed several techniques for creating free-standing structures out of the liquid metal. One technique involves extruding tiny droplets onto a platform. Normally the droplets would join together and turn into a small puddle, but thanks to the thin oxide layer that forms on the surface of each droplet they keep their shape and become stackable. You can view a video of the process here:

During trials, the researchers have already successfully used their printer to build wires, arrays of spheres and arches out of metal. They also believe this printing method could be used to make a variety of electronic components in the future.