Last month, Alex Madinger appeared at a TedX conference in Columbia, Missouri, to discuss his passion for 3-D printing. Madinger was president of the 3-D printing club at the University of Missouri, where he’ll graduate with a degree in mechanical engineering next weekend, and then plans to start his own 3-D printing business. Today on America Weekend, I asked him to explain how 3-D printing works, how it makes innovation cheaper, and how it can be used to manufacture personalized products and even human body parts. We also discussed the controversy about making guns with 3-D printers. Listen, then click here to subscribe to these podcasts via iTunes!