Sand Casting

Sand casting involves placing a mould and 'ramming-up' moist a mixture of moist sand and sodium silicate into a core box over that mould. The sand mix takes about 10-30 mins to harden. The mould and casting can then be removed and metal can be poured into the cast. This is then left to cool and harden. Weight are placed on top of the cast to ensure that they are firmly pressed together. The mould can then be removed and the cast placed into a 'shake out' machine where it falls through a grate and is re-processed. Any remaining sand on the mould is removed by shot blasting.
The mould is sometimes heat treated to improve strength. This involves heating castings in an oven then rapidly cooling them in water. The product can then be sent to casting.