Moulders cast molten metal into moulds to produce solidified castings.
They first prepare and shape the sand in which the mould is to be formed. They then prepare the core or inside of the casting by means of a core box and place the pattern into the moulding box. They pack sand firmly around the pattern to impress its form in the sand ensuring that moulding boxes cover the top faces. Heavy castings are formed by holes being dug in the ground and lined with sand or brickwork. The pattern is then removed and the mould dusted. Once the mould is dry, molten metal is poured through runners into the mould.
After the cast metal has cooled down, the mould is broken away and the edges of the solidified casting are smoothed before it is finally machined. Because moulds are exposed to very high temperatures and pressure during the moulding process the moulds must be of a high standard. Moulders work in foundries.