green sand casting surface finish_green sand casting surface finish

The primary material in sand casting is, unsurprisingly, sand itself. The most commonly used sand is silica sand, due to its excellent thermal stability and ability to retain shape. Silica sand particles are usually angular or sub-angular, which enhances the strength of the mold. Another type of sand occasionally used is olivine sand, which contains magnesium iron silicate and is prized for its high melting point and minimal expansion. When selecting sand, it's essential to consider its grain size, shape, and cleanliness, as these factors directly affect the mold’s permeability and surface finish.