ph4cr writes with news that a few researchers have discovered an alloy that allows them to print 3D structures from liquid metal at room temperature. From the article: "'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, an assistant professor of chemical and biomolecular engineering at NC State and co-author of a paper describing the work. ... One technique involves stacking droplets of liquid metal on top of each other, much like a stack of oranges at the supermarket. The droplets adhere to one another, but retain their shape – they do not merge into a single, larger droplet. ... Another technique injects liquid metal into a polymer template, so that the metal takes on a specific shape. The template is then dissolved, leaving the bare, liquid metal in the desired shape. The researchers also developed techniques for creating liquid metal wires, which retain their shape even when held perpendicular to the substrate." The paper is available online. There's also a video of the process in action, below the fold.