High Density Foam

This silky-feeling, dense foam is a most versatile material. It is very lightweight, quite stiff, but bendable, about 1cm thick. It is made from expanded polyethylene (known as polythene or plastazote in the UK): the same stuff as shopping bags. Over sixty million tonnes of this material is produced worldwide every year, which is even more than it sounds as it’s so lightweight.

This foam is expanded at the liquid stage using nitrogen gas to form a closed cell foam. This means that it is full of individual air bubbles which are not connected, giving the foam a robust, regular structure. If you squash the foam, it will immediately spring back to its original shape, making it a good material for indestructable children's toys.

It is also a very efficient insulator, and its cell structure makes it incredibly buoyant. Nice chunks of this, when teamed with the doggy-paddle, have helped millions of people to learn to swim over the years. It machines well and is able to hold a precision edge, is non-toxic, inert and acid-free, so it won’t react, harbour bacteria or degrade. This makes it ideal for custom cases for transporting and storing fragile or expensive items or medical equipment.