Polyurethane foam comes in solid and springy formulas. Solid foam has many uses such as for temporary stages and flooring, wall insulation, theatre props, coolers and boats and aeroplanes. The soft foam is used for packaging, padding, seat cushions and bedding. You can make either kind of foam using two-part foam mixtures. When working with the mixtures, make sure to wear eye protection and a respirator mask to protect your eyes and lungs when working with the semi-toxic materials.
Choose a mould for the foam that you want to make. Solid foams are typically used for things such as wall insulation, theatre props and siding for boats. Use a mould for whatever object you want to create with the foam.
Spray the mould with a mould-release spray. Allow the spray to dry for 24 hours before adding the foam liquid.
Mix the two parts of the foam with an even 50-50 split between the two mixtures in a large, disposable container. Stir the two mixtures together with a stirring stick.
Pour the liquid into the mould within 15 minutes of mixing the liquid. The foam starts to set within 15 minutes.
Wait for the foam to cure overnight. Keep the mould in a room that is around 21.1 degrees Celsius so that the foam can cure. Colder temperatures will prevent proper curing. Pop the foam out of the mould after 24 hours.
Follow steps one and two as outlined above for preparing the mould for the foam.
Mix the two parts of the urethane foam mixture together with a ratio of 28 parts of hardener and 72 parts of urethane foam liquid. Mix the two parts together until they start to expand.
Pour the foam into the mould. Leave a small amount of room for expansion. The foam should be fully expanded within 15 minutes.
Allow the foam to cure for 24 hours in at least 21.1 degrees Celsius.