When you were a kid, maybe you built a parabolic solar cooker as a science project and thought you were pretty hot stuff. (Zing!) Markus Kayser, who is not a kid but clearly has the lateral-thinking skills of one, did something much more impressive: he built a working 3-D printer that uses the sun's rays to sinter solid objects of out desert sand.
His demo video is about as pulse-poundingly paced as an Antonioni film, but that's appropriate given how slowly Kayser's "Solar Sinter" device works in real life. "In this experiment, sunlight and sand are used as raw energy and material to produce glass objects using a 3-D printing process that combines natural energy and material with high-tech production technology," he writes. Sintering is a technical term for "melting powder into solid objects," and selective laser sintering is a common 3-D printing technique. Kayser realized that the world's most powerful laser is right above our heads, and to conduct his experiment at maximum sintering strength (and also afford himself with abundant, free printing material), he dragged his rig out into the Sahara Desert near Siwa, Egypt, and got to work.
The results aren't going to win any industrial design awards: the sintered sand congeals in craggy layers that look like a baking experiment gone wrong. But because the device is computer-controlled, the overall shape -- as with any 3-D printed object -- is preternaturally precise: Kayser printed out an abstract sculpture of intertwined cylinders and a mathematically perfect-looking hemispherical bowl. Kayser doesn't consider his device necessarily useful in its current form, but rather as a proof of concept for "explor[ing] the potential of desert manufacturing, where energy and material occur in abundance." Looking at Saharan sand melting and bubbling under the sun's glare, it's hard to disagree with his first principles.