the world of hand-moulding materials: a reference guide

Putty World

An independent reference guide to hand-moulding materials. It is not a shop, sells nothing and has no connection with the former website on this domain; before buying for a child, check the age shown on the pack.

What is putty

What is thinking putty

Thinking putty, also called hand putty or smart putty, is a moulding material you squeeze, stretch, tear and gather back into a lump. It doesn't harden like clay or hold its shape like classic plasticine, but it can flow one moment and bounce the next. This page explains what the material is, what varieties exist, how to choose it by age and how to make it last longer.

What surprises people about thinking putty is that it seems to have two personalities. Pull it slowly and it stretches like dough; strike it sharply and it bounces like a ball. The secret isn't magic but the properties of the polymer.

— Editor's note

History of this address

Archived address · now a reference page

This address used to be a section of an online shop that sold thinking putty. That shop has closed, and our guide has no connection with it.

It is now a reference page about the material itself. We sell nothing, name no brands or prices and take no orders; we only explain how thinking putty works and how to handle it.

What it's made of and how it behaves

Thinking putty is a material based on a silicone polymer. Its key feature is that its behaviour depends on how quickly force is applied. Pull or knead it slowly and it flows and stretches almost endlessly; strike it sharply and it responds like an elastic solid, even bouncing off the floor.

The material has an unusual history. It was created in the 1940s during a search for a rubber substitute. It never became one, but it has been sold as a toy since 1950 and has kept its fans ever since.

What varieties exist

  • Plain putty in a single colour: the simplest way to get to know the material.
  • Pearlescent and glittery putties with reflective particles added.
  • Thermochromic putties that change colour with the warmth of your hands.
  • Glow putties that glow faintly in the dark after being exposed to light.
  • Magnetic putties with ferromagnetic particles: they are drawn to a magnet, but sold with a strong magnet they are not suitable for children.

How to choose by age

  • First of all, find the age marking on the pack and stick to it.
  • If a child still puts everything in their mouth, it's better to hold off on moulding putties.
  • For children, choose sets without small parts and without magnets.
  • Check that the tin closes tightly and that the child can open it easily under supervision.
  • Keep the packaging with the ingredients and instructions, at least at first.

Care in a nutshell

  • Play with clean, dry hands on a smooth surface.
  • Store the putty in a closed tin in a cool place.
  • If putty sticks to fabric, chill it and don't rub.
  • More detail in the practical article on storage and cleaning.

Sources and basis of this text

  • TR CU 008/2011 «On the safety of toys» (Eurasian Customs Union regulation, in force in Russia, Belarus, Kazakhstan, Armenia and Kyrgyzstan; other countries have their own toy-safety rules)
  • Manufacturers' instructions and labelling for moulding putties (general principles)
  • Materials on the safety of children's toys (general principles)

Ingredients, labelling and manufacturers' recommendations change over time, so the instructions and markings on the pack of the specific product are always your main guide. This reference explains general principles and does not replace a doctor's advice if something goes wrong.