Loam Moulding

LOAM MOULDING:

          Loam is one type of clay which is made with sand mixed with water to form a thin plastic mixture from which moulds are made. Loam sand also contains ganisters or fire clay. The loam must be sufficiently adhesive so that it can cling to the vertical surface. It always requires special provision to secure adequate ventilation. The object is opened out pores in the otherwise compact, closely knit mass, by artificial means. There are various kinds of organic matter such as chopped straw, and particularly horse manure, is mixed up with the sand, a typical loam sand mixture is given below :

1.	Silica Sand	22  vol.
2.	Clay	5    vol.
3.	Coke	10  percent
4.	Moisture	18-20 vol.

          This applied as plaster to the rough structure of the mould usually made of brick work and the exact shape is given by a rotating sweep around a central spindle. Cast iron plates and bars are used to reinforce the brick work which retains the moulding material. Loam moulds also be prepared by the use of skeleton pattern made of wood. The surfaces of loams are blackened and are dried before being assembled.

          Loam moulds are employed chiefly in the making of large casting for which it would be expensive to use full pattern and ordinary flasks equipment. Objects such as large cylinders, chemical pans, large gears, round bottoms, kettles and other machining parts are produces in the loam moulding.