To build up the thickness required, it is usual to laminate pieces to form the mould.
Two pieces will suffice in this case because of the width of the starting material - meranti.
Glued and screwed together here is the finished mould in two parts - necessary so that they can be easily removed after the body has taken shape.
The waste pieces from the middle are important and need to be kept. These will form the mating parts that support the sides and help them hold their shape until they dry and the glue is set.