Introduction: Custom Moldable Fidget Spinners

About: Kids Invent Stuff is the YouTube channel where 4-11 year olds have the chance to get their invention ideas built by real engineers. We do this to get more primary school kids interested in engineering. Kids a…

Here's how to build your own customisable fidget spinners our of hand-moldable polymorph plastic that melts easily in hot water. This is a great project for parents and kids to do together and doesn't require any special skills or expensive equipment.

We set this challenge for our recent Big Inventor Little Inventor episode and Rosie (age 7) and Felix (age 9) came up with 14 different spinner designs, complete with glitter, googly eyes and glow-in-the-dark powder!

If you're looking for further invention opportunities for kids, then check out our YouTube channel: Kids Invent Stuff. Every month we set a different themed invention challenge and invite kids to send us their invention ideas. And every month we pick one idea and build it! For example Ruby (age 7) who challenged us to built a pair of shoes to walk on water.

Step 1: Some Inspiration

Have a watch of our Big Inventor Little Inventor video to see how Felix and Rosie made their Polymorph fidget spinners.

Step 2: Tools & Materials

To build your own polymorph fidget spinners you'll need:


  • Kettle or stove to heat water
  • Metal pan or bowl
  • Serving/dessert spoon


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Step 3: Melt Your Polymorph

Polymorph granules start melting in water over 40°C (104°F), so just pour them straight into hot water to get them melting. We find it easier to do this with a pan on a stove, so you can control the temperature easily. But you can boil a kettle first to speed up the process. You can mix different coloured granules to achieve whatever colour you like. It's worth noting that even a small amount of the darker colours (blue, red, black) will make the lighter colours turn dark quite quickly.

You can tell your Polymorph is melted when it starts to go clear and
looks a bit like molten gummy sweets. (although we wouldn't suggest eating it!).

Step 4: Mold Your Spinner

Once your Polymorph is melted, you can remove it from the water with a spoon (being careful not to burn yourself). Polymorph plastic hardens as it cools, so the trick to working with it is to be quick when molding it and to keep your hands wet so it doesn't stick to you too much.

As far as designs go, the shape, size, colour etc is entirely up to you. We let the kids decide (which is how we ended up with one that looks like a dog poo!).

You can combine different parts of different colours and mold together multiple colours for a marbled, rainbow effect.

Step 5: Accessorise

You can add glitter, googly eyes and glow powder to make your spinners even more awesome.

The eyes can be pushed into the plastic while it's still moldable and the glitter can either be worked into the plastic before you shape it, or pushed into the surface while it's still sticky.

For a glow-in-the dark spinner you work glow powder into the plastic before you shape it, just like the glitter. But be careful not to add too much as it can make the Polymorph quite dry. The powder is great fun because it does temporarily make, hands, fingers, noses etc glow too!

Step 6: Spin, Spin, Spin

Once you've made your spinners it's time to get spinning!

And the best thing about Polymorph is that when you're bored of your spinner you can just stick it back in some hot water and melt it down to make something new. The ultimate recyclable toy!

Let us know if you build your own spinner. We'd love to see it.

Keep inventing!

Note: Always be careful around hot water (particularly with kids). It's not fun getting burnt and adults hands are often much less sensitive to heat than little people's hands.