Can appropriate and workable material is high refractoriness in nature can be used for model making. Thus, the material can be made to mold metallic or non-metallic. For the category of metallic, common materials cast iron, mild steel and alloy steels. In non-metallic molding sand group, plaster of Paris, graphite,and ceramics included. But, out of all, the sand molding material molded non-metallic most common use due to their properties inherent in certain namely refractoriness, chemical and thermal stability at high temperature, high permeability and workability as well with good strength. Furthermore, it is also very cheap and easily available.
There are different types of sand refractory used for molding: (i) silica sand (ii) magnesite (iii) Zircon (iv) Silimanite (v) Olivine (vi) Sand Graphite / carbon used in foundries to be able to have the The high temperature days and should not fall under the burden prevailing. Silica sand is used mainly in foundries because of the following. 1. It’s a very good refractory material and fuse or soften even at very high temperatures, ie 1650 ° C, when in contact with molten metal. 2. They can be easily molded into intricate shapes. 3. They have enough porosity or permeability and allow easy escape of gases produced by molten metal and other bonding ingredients. 4. They can be used repeatedly for making molds after addition some bonding material. 5. They are cheap and easily available. 6. They are immune chemical with molten metal. 7. They do not rot. A disadvantage is the more high coefficient of thermal expansion (above 560T).
Sand is used in foundries available beds (in) River: Sand Molding Molding sources. (ii) the Sea. (iii) Deserts. (iv) Lakes.