Wednesday, May 5, 2021

Craft It Out: Thermoplastic Pellets

One of my goals for this blog in 2021 is to try new crafty stuff out on my own dime.  Testing out products I've never used before, techniques that are new to me, etc. and doing it with my 11yr old daughter as a sidekick to see how kid-friendly things are.  I figure as we learn, and do a bit of trial & error, that might help other crafters too.  So today I'm jumping right in to my first Craft It Out segment with Thermoplastic Pellets

I bought a bag of these at a Maker Faire many years ago.  At the time they were advertised as being great for prototyping maker-y stuff, but I thought maybe I could craft some stuff with them.  I got them home and promptly forgot about them.  Then when I was looking for something recently I saw the bag at the back of a drawer & thought it was about time I finally gave them a go.

So, what are Thermoplastic Pellets?  Non-toxic, lightweight polyester plastic that comes in pellet form that, when heated, is moldable like putty to be used in all sorts of ways.  There are lots of brand names out there, but they all work pretty much the same way.  

What can you make with Thermoplastic pellets?  What's cool about them is how infinite the uses are.  Literally anything you can dream up that could be made with plastic - jewelry, craft projects, props or costume pieces, custom parts, artwork, ergonomic handles, game pieces or even repair tools & toys with them.

How do you mold with Thermoplastic pellets?  You can sculpt with your hands like you would with clay or you can use a mold to get your shape.  Just make sure said molds are heat resistant - metal or silicone seem to work best.  

How does it work?  Like the name says, you have to heat the pellets (to around 150F) get them to melt and become a pliable putty.  I tried a couple of the recommended heating techniques with mixed results.

What seemed like the easiest method, just pouring some pellets into a mold and popping it in the oven was a total hassle.  It took FOREVER for the pellets to melt.  As in 4 times as long as recommended.  One limitation of thermoplastic is you don't want to overheat it, so just turning up the temperature isn't really an option.

After a long while the pellets finally did melt and turn clear.

But gravity meant they slumped down and left these streaky "wings".  I felt like yes, this was "minimal effort", but took way too long & with not ideal results.  
Oven method? It's a NO from me.

Next I tried the hot water method.  I used an electric kettle with a digital temperature setting to get my water to just above 150F, then poured it into a Pyrex bowl that I had on an electric mug warmer to keep the water at temperature.  
Hot water method:  YES!!

Once all the beads were clear, I swirled them to stick together with a metal awl to get them out of the water.  

Then we began to knead it to get the moldable putty consistency.  I'll be honest, this part was so cool to see & feel - it was hard to believe this was the same stuff that was hard white plastic pellets just minutes before:

At this point we learned that you have to work really fast because the consistency gets stiffer and harder to shape fully.  We pressed some into our silicone molds like this:

There were a few times we had to return our plastic to the hot water to soften it up, but just a few seconds gets it back to the right consistency.  Another hot water technique recommend a water-filled pan on an electric griddle (which we didn't have), which would probably be best if you're doing a lot at once.

Some we rolled out flat like dough, then used metal cookie cutters to cut out shapes.  We also rolled a few into balls.  Since it doesn't stick to stainless steel or wood while warm, you can use a wooden skewer to make holes, which is how we crafted a few beads and buttons:

To cool them down fast you can stick everything in a pan of ice water and they'll harden up in a minute.  You can tell they're done when they are completely white again:

Reusability for the win!  One of the best features of thermoplastic is that it can be remolded again if things don't turn out.  And we had quite a few that didn't look great as we were getting the hang of things and weren't moving fast enough!  Just stick it back in the warm water and wait for it to turn clear to try again.  This was a big plus.  You can also use an x-acto knife or Dremel tool to remove excess bits of plastic from designs (and chuck those scraps back in the hot water to reuse too!). 

What about coloring?  I saw a number of videos that showed how to knead in alcohol inks or pigment pellets to color the plastic completely.  I didn't have any of those on hand so I couldn't try them, but they sounded do-able - although messy - so gloves would probably be a good idea with that.  Since the plastic starts hardening pretty quickly out of water, you'd also have to be lightning fast to blend it in before having to pop it in the hot water to soften it again to shape.

Painting the exterior is a much easier option.  Basic acrylic craft paint is ideal for that.  
We did ours on freezer paper so nothing would stick:  

I did this robot with acrylic silver metallic paint:

For this butterfly we made into a pendant, we used a metal mini cookie cutter for the shape, skewered a hole and then painted it with matte acrylic paint and then a layer of silver fine glitter paint on top.  

For this cross pendant we used a metal cutter and then painted it with pearlized acrylic paint:

We're planning to glue magnets to the backs of the robot, puffy heart & penguin.  Now that we're more seasoned with what set-up works best & how the pellets work, I think we'll try doing more free form shapes & look for some interesting molds...maybe even have the kids design their own custom game pieces.  

 One bag can make LOTS of things and clearly from the fact ours was more than 5 yrs old, it doesn't have an expiration date, so it's pretty economical.  The only real limits seem to be getting imaginative with using them.  We're still brainstorming more things to create and maybe come up with some new takes on technique/use.  I'll share our findings when we do!


  1. So interesting! thanks for sharing on craft schooling Sunday, great to see you!

    1. Thanks - I haven't seen many crafters using it so it seemed good to share. Good to be linking with you again!

  2. I had a tub of these a few years ago, I found the hot water method was the easiest too. I made a few fun things with it. I like the fact you could just heat it up and go again if it didn't turn out well too.

    1. That was a big plus to me too. There's always a learning curve with new craft materials and some can be quite pricey to mess up with. This one gave me a bit more leeway to try things.


Getting your comments brightens my day. I'd love if you left one:)


Related Posts with Thumbnails