Casting aluminium in plaster is a very simple process that can be done from home if needed. The process of casting a metal in plaster can be done for many of the metals with a low melting temperature, such as copper, magnesium and zinc. The plaster cast will only be good for one-time usage, because it is broken to reveal the aluminium. So, if you intend to use it more than once, you will need to make several moulds.
Mix the plaster with talc, sand, sodium silicate and water to form a liquid substance.
Pour the liquid into a spray bottle and spray the mixture on polished brass pattern halves. The liquid needs to be at least 1.5mm thick to form a sturdy mould.
Dry the liquid for about 15 minutes in the mould. After this, extract the mould and dry it in the oven for 30 minutes at a temperature of 54.4 to 65.6 degrees Celsius.
Pour the molten aluminium in the plaster moulds.
Break the plaster moulds and wash the aluminium to remove any signs of the plaster casing.