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In the Maker Shed: ShapeLock

Science Workshop
In the Maker Shed: ShapeLock

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!

18 thoughts on “In the Maker Shed: ShapeLock

  1. Todd Burlingame says:

    Microwaving it makes it pourable. Very hot, experiment with caution.

  2. zephyrin says:

    will it stick to other plastics?

    1. M. Kelsey says:

      “… easily bonds to other plastics when hot.”

  3. Nathaniel says:

    I read somewhere that this substance give of moisture after a certain period of time, is this true?

    1. kongorilla says:

      I don’t know about moisture, but it does change over time. It starts out very strong, but over a period of years it becomes very brittle. I made many items with PCL in the late 80’s and early 90’s, and all of those items subjected to ANY force crumbled to bits within 10 years or so. Similarly, the unused pellets no longer melt completely anymore, and when they harden, they’re a brittle, flaky mess.

      So, this stuff is great for prototyping and having fun, but don’t make anything you want to last or is stressed for a long time.

    2. Michael Castor says:

      Since it’s common to heat it in water, I suppose that it’s possible that moisture can become trapped in it and come out over time.

  4. Keith Olson says:

    FYI, you can also buy 1KG tubs of it from

  5. edward a. penalber says:

    Just ran across this amazing product,while surfing.think it may be applied towards my artist sons mixed-media projects.where can i order,or get more info on this product?

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I am the Evangelist for the Maker Shed. It seems that there is no limit to my making interests. I'm a tinkerer at heart and have a passion for solving problems and figuring out how things work. When not working for Make I can be found falling off my unicycle, running in adverse weather conditions, skiing down the nearest hill, restoring vintage motorcycles, or working on my car.

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