split and flat back), moulding, melting and pouring, dismantling and fettling. 6.4 Core making (box, sand). 6.5 Casting defects (types and causes) 6.6 Safety precautions.

Mould making is the process of creating a cavity in sand where molten metal will be poured to form a solid object. Think of it like making an imprint in sand at the beach. You pack special casting sand around a wooden pattern, then carefully remove the pattern to leave a hollow space. This hollow is your mould. The two main types are split moulds, which separate into two halves, and flat back moulds, which have one flat surface. Once your mould is ready, you pour hot molten metal into it. The metal fills the cavity and takes the exact shape you wanted. After cooling, you break open the mould to remove your finished metal object. In Nigeria, artisans in places like Ikeja and Oshogbo use this traditional method to cast brass locks, cooking pots, and decorative items. The skill requires patience, precision, and understanding how sand behaves when compressed.

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A pattern is the replica of an object you want to cast in metal. Think of it as a temporary model made from wood, metal, or plastic that you press into sand to create a mould. The pattern must be slightly larger than your final product because metal shrinks as it cools—this is called allowance. Nigerian craftsmen making brass door handles or cooking pots use wooden patterns pressed into moulding sand to shape their moulds before pouring molten metal.

Patterns come in different types: single piece patterns for simple objects, split patterns divided into two halves for complex shapes, and flat back patterns with one flat surface. Each type serves specific purposes depending on your casting design. Good pattern making requires precision because any errors in your pattern will appear in your final cast product.