PCL plastic

Polycaprolactone (PCL) is a boil-to-soften plastic that's hand-moldable, which makes it very useful for hobbyists. It's sold under many different names like Polymorph, Shapelock, Instamorph, TechTack, etc.

Few other plastics have a similar softening temperature range that allow it to be so easily shaped using basic home tools. (hot glue is one, but PCL is far firmer than hot glue after they both cool, and IMHO PCL is all-around a stronger and more secure product) (PCL does require a staking technique to make it bond well to other materials, while hot glue has inherent adhesive properties, but staking results in a much stronger bond)

PCL sticks to nearly everything when it's hot. It's not really sticky when cool, but it's still useful to know what materials it sticks less well to when it's in a more malleable temperature range:

• metals (make sure the metal surface is bare and very clean)
• silicone
• delrin / acetal
• nylon
• teflon (PTFE)
• polypropylene (PP)
• FR-4 glass epoxy (PCB)
• glass — allows you to see through the material and observe the state of the plastic beneath, when you're in the process of smashing it flat with the glass
• nitrile gloves — very useful when dying PCL plastic (TODO: Check if latex medical gloves would work. Nylon food-service gloves DEFINITELY stick to PCL plastic.)

Fabricating techniques:

• voids / bubbles — how to avoid them?
• surface finishing — use flame heating, or better yet, the back of a heated spoon
• you can cast it with itself???? !?
  • Ways to avoid sticking to itself: Cool the surface a bit first, or coat the surface in grease or cling wrap.
• As with all plastic welding, be patient and understand that the thicker the plastic, the longer it will take to heat all the way through. A shorter time at a higher temperature won't work, instead use a longer time at a lower temperature.

Shaping techniques:

• flat sheet — use a rolling pin (better yet, a pasta machine) [1] [2]
• filament stick — cut a strip from a flat sheet, and roll it on a flat surface until it's round

Pigments / dyes / colors:

• InstaMorph sells their own pigments, but a variety of other pigments work ok, including paint powders, alcohol-based inks, and epoxy dies.
• use this technique to mix in / spread out the color
  • a similar lengthy process
• Tiffany suggests using the same technique that bakers use to fold butter into dough

Webpages that discuss techniques: [1] [2] [3]