Foam Washer

This washer, or spacer, is made from an ultra-light but chunky, densely-textured foam. It is made from polyethylene (known as polythene 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. It is expanded during its 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. This makes it a good material for washers like this, which need to act as cushions between parts of a machine or structure. It is also a very efficient insulator for sound and heat, and it will not conduct electricity. In fact, its total inertness makes it suitable for all sorts of tricky applications as it’s non-toxic and acid-free, so it won’t react, harbour bacteria or degrade. It machines well and is able to hold a precision edge. This makes lightweight washers like this ideal for custom packaging, for transporting and storing fragile or expensive items, or medical equipment.