Construct a mould box using either balsa wood or lego bricks.

To reduce the amount of rubber used, ensure that the box is only a few centimetres larger than the item to be moulded.

Lay the mould box on a flat surface and fill with a soft clay, such as plasticine, to halfway.

Ensure that the clay is flat and smooth. Water or acetone can be used to ensure optimum smoothness.

Press item to be moulded halfway into the clay and use a pen to create registration keys.

If the item is fragile, then first create an indentation in the clay, place the item into indentation and then build up clay. Ensure that surface of clay remains level and smooth.

Apply release agent over the model, clay and inside walls of mould box.

Mix and gently pour Sylmasta moulding rubber into mould box, ensuring at least 1.25cm depth over highest point of item. Leave the rubber to cure.

Note: see instructions for mixing ratio and cure time for moulding rubber.