We had an idea to try and make a cast object using polystyrene. We made a cast polystyrene stepping stone for a the garden.

We used a latex mould that we already had available, funny enough. Just happening to be hanging around in a garage.

We took a load of scrap blocks of expanded polystyrene and dissolved it in bucket of acetone. We kept adding the expanded polystyrene until the acetone disappeared and we were left with a blob of polystyrene.

We then took the blob of pliable polystyrene that had the consistency of dough and kneaded it into the latex mould. We then placed it in the garden, loosely covered with a upside down bucket to stop it from getting wet and waited, and waited and waited, for about a month for the polystyrene to harden.

We now have a new stepping stone for the garden made of solid polystyrene.