Practice For Preparation of Molding Sand Mixtures

Silica sand (SiO2) is used more frequently for making castings than any other moulding materials. It is relatively cheap, and has sufficiently refractoriness even for steel foundry use. A suitable bonding agent (clay or molasses) is mixed with the sand; mixture is moistened with water to develop strength and plasticity and to make the aggregate suitable for molding. A definite mulling action is always required for thorough mixing, in which sand grains, bonding agent, and water are rubbed intimately together. Different types of sand mullers are used to serve this purpose.

Equipment:

• Sand Muller


• Hot Tray


• Shovel

Chemicals / Materials:

Sand, Molasses and Water.

Procedure:

1. Take silica sand and stack it over hot tray with the help of a shovel.


2. Put on the fire and heat the sand for sometime.


3. When it is sufficiently hot, throw it into the pan of muller with a shovel.


4. Then add some amount of molasses in the sand and switch on the muller. The wheels rotation inside the muller will thoroughly mix up sand and molasses.


5. Continue adding and mixing molasses in the sand until sufficient strength and plasticity is developed in the sand-molasses mixture.