11. Patterns used in sand casting may be made of wood, metal, plastics or other materials. 12. Sand casting involves the use of hot molten glass poured directly into a preformed mould.13. The gas flow past the rough sand castings could be greatly improved by polishing the passages. 14. This dry sand casting process results in a more rigid mold better suited to heavier castings. 15. Sand casting allows for smaller batches than permanent mold casting and at a very reasonable cost.16. Full-mold casting is an evaporative-pattern casting process which is a combination of sand casting and lost-foam casting. 17. It uses an expanded polystyrene foam pattern which is then surrounded by sand, much like sand casting . 18. Sand casting is one of the earliest forms of casting practiced due to the simplicity of materials involved.19. It can be more expensive than die casting or sand casting , but per-unit costs decrease with large volumes. 20. "' Core plugs "'are used to fill the sand casting core holes found on water-cooled internal combustion engines.
