Casting a Milk Bottle

Milk bottles are made from high-density polyethylene. For this cast I melted 5 milk bottles and compressed them in the wooden cube mould. Weight needed to be applied quickly to press the molten plastic into the shape – I stood on it for about 5 minutes and then set the weights in place to keep the pressure as it cooled. HDPE contracts as it cools and without the weight it would quickly lose its shape and its relatively flat surfaces.