Dual extrusion systems for 3D printers have been around for quite a few years, but the additional cost, complexity, and hassle of printing with them have kept them off the workbenches of most hackers.

The next frontier of desktop 3D printing is multi-material and multi-color prints. Right now, you can buy a dual toolhead for a Lulzbot, and dual toolheads from other companies exist, although they ...