The first time I used ShapeLock was in my hotel room at Maker Faire: Bay Area. We needed some sample objects made for display in the Maker Shed so I cooked up some ShapeLock using hot water from the coffee maker to soften the plastic beads. After I hand-molded and cooled the plastic I was left with a solid, man shaped doll that I couldn’t break despite my best efforts (even using the hotel room door and dresser!) Ever since then I have been hooked to this terrific material. It’s perfect for prototyping, making custom parts, and can be used in a variety of projects. I even used some to fix my washing machine. But “what is it” you ask?

The technical name for ShapeLock is Polycaprolactone (PCL.) It’s a biodegradable polyester that has a low melting point of around 60°C (140°F). It has physical properties similar to nylon when cool and has a putty like consistency that easily bonds to other plastics when hot. It is classified as an ultra-high molecular weight low temperature thermoplastic and with a density of 1.145 g/cm3. PCL is commonly used in the manufacture of polyurethanes and was one of the first raw materials extruded through a RepRap extruder. It’s also marketed under the names Polymorph, InstaMorph, CAPA, and Friendly Plastic.

If you’re the least bit interested in advanced materials or just want some of this wonderful stuff, I highly recommend picking up a bag from the Maker Shed. I find it nearly as useful as duct tape!