Polymorph In Practice


[Leesam] tipped us off to this cool tutorial for shaping Polymorph. For those who haven’t, it is pretty cool stuff. It is a plastic that comes in little pellets. You can melt it down at relatively low temperatures and mold it to the shape you need. We’ve seen it used on several projects, most notably CrabFu’s swashbot3. Generally, we see it hand shaped, so it is fairly organic and imperfect. It can be used for more precise shapes though. This tutorial walks us through the easiest way to produce sheets of the stuff to be cut and bent into brackets as well as some helpful tips on getting the best results.

22 thoughts on “Polymorph In Practice

  1. I got a jar of this for christmas, it’s fun to play with.

    His directions kind of worry me… Just follow the directions that come with it. 140°-150°F water, let it warm until it’s clear, and use popsicle sticks (doesn’t stick to wood). Can’t burn yourself that way.

  2. I love this stuff, but that guy is waaaay too paranoid about burning himself – you can melt Polymorph / Shapelock in a bowl of boiling water, fish it out with a spoon, and mold it by hand immediately without it being the least bit uncomfortable to hold.

    The only thing to be wary of is if you start with the pellets, you can get pockets of hot water trapped inside the plastic that will be painfully hot if they leak onto your hand while squishing the plastic together. Use tongs or a fork until it’s all smooshed into one solid mass, then hands are fine.

  3. hmm.

    a little while ago i discovered that a hobbyist “heat pen” from a local craft shop works perfectly for this application.
    gets just hot enough to reliably melt the polymorph but not so hot as to create ouchies.

    I also found at the same time that mixing a little glow powder (strontium aluminate) with the polymorph makes Glowymorph (patent pending) :)
    used it to make a few fishing floats and it works well.

    Note that this will not work with the hot water technique as the aluminate is water sensitive.
    if you have bad aluminate put some in a crucible and heat in an oven at about 150C or so for an hour then immediately put it in a box with prepared silica gel to absorb the rest of the moisture.

  4. Interesting. Never heard of the stuff.

    When I needed a custom plastic piece in the past, I baked some PVC pipe in my oven until it became soft… It had a tendency to roll itself back up, but it worked out reasonably well.

  5. @ch, there’s a trick to it.
    you need to get it well above the melting point (around 80c or so) and use powder based pigments.
    then fold a “parcel” of the pigment into the plastic and knead thoroughly.

    one good source of these is an craft shop (I got mine from Oatlands) that sells heat fusing powders.
    i bought a bunch of these for £2 each and they last forever.

    have used it to repair power connectors etc.

  6. These things are generally called “thermoplastics” and come in many forms; sheets, Pellets, fabrics, meshes and possibly more.

    We use them to make are stuff and prototypes for molds.

    It goes by many names, but the one I use is “Proto Plast”. Where I buy it, I can get a sheet of “off spec proto plast” 18″ x 24″x 1/8″ thick for $30. (off spec means it is a weird color or has scuff marks or something, but it still works great)

    Try this site under the section “Thermoplastics” in their “cyberstore”:

    They’re a S.F. Bay Area art supply dealer that we deal with in California, USA.

    All kinds of good hackish products for you there, with many kinds of innovative uses.

    -Louis II

  7. For the very talented scrounge, though, one can use the plastic from their food safe plastic milk jug containers to similar ends… put it in some hot water… violence, you have a plastic that is good for a few more mold jobs… not as reusable as the other kinds mentioned above, but still worth it’s price of free!

  8. @tweaq

    friendly plastic looks similar, but are you sure it’s the same stuff?


    It’s the kneading it at 80C taht’s hard. First, you have to heat w/o burning the plastic. Then you need to knead while ensuring it stays hot. total PAI!

  9. Why is he going to all the trouble to melt, pour and flatten a relatively expensive craft material just to cut it and _re_bend_ when he could have bought sheets of plain styrene plastic that modelers use, for very little cost? It’s available from plastics suppliers or if you want small pre-cut bits, just buy Evergreen at your local hobby store.
    The mind boggles…

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