PREPARING THE CLAY MOULD OUT OF THE WAX MODEL

After completing the wax model it is mounted on a wax base which is in turn attached to a wax rod in the shape of a funnel called the runner. This is to serve as the outlet for the moltern wax when the clay mould is heated for casting. The stapathy also attaches connects different portions of the image with wax rods to facilitate easy running of molten metal alloy in to all parts simulataniously. Such roads also serve as additional support to the image when cast in metal while the stapathy works on the cast model with hammer and chisel to give finishing touches. The wax model is coated with finely ground clay in semi-solid paste from mixed with charred husk and cowdung. The first coating is applied in a semi solution from and allowed to dry before second coat is applied. This process repeats several times till a fine layer of loom is spread out over the entire wax model surface. It is important that no portion of the wax model escapes coating of clay and preserves the details of the wax model worked by the stapathy. The clay should be of fine texture to preserve the intricate details of the modeling and strong enough to withstand the hot liquid metal when poured into it. For this clay collected form ant-hill is most ideal. The model is then encased in several layers of coarser clay material each successive layer be-coming coarser and bulkier. Finally a fine strip of steel or wire is tied round the entire clay mould taking care to preserve in tact the wax oxifice that should serve both as runner and vent while casting. When the clay mould is dry enough and strong to withstand subsequent operations the wax inside the mould is removed by heating the mould over a drafted ground furnace The wax melts and runs out which is then collected and weighed in order to ascertain the quantity of metal to be taken for casting.