One of the projects in my list of stuff I’ll get around to is making a 3D unprinter: a machine that can melt a thermoplastic object down and extrude it back into filament.  McMaster has this cool course called Sustainable Future, and part of the course is for the students to do a real world project involving sustainability.  I pitched the idea to the class, and I’ve got a team of 4 students now working with me to build one!  We’re blogging here, and we’ve set up a github repo here.  Watch our progress, we should have a good prototype by December.