To improve the surface finish of
casting, the following additive is used in the moulding sand
Resins
Oils
Wood flour
Sea coal
Resins
Resins are used in the moulding sand
to improve the surface finish of casting.
●Resins are natural or synthetic gum
with high melting points like phenol formaldehyde, phenolic-urethane and furan.
●It has a good collapsibility, low
gassing and capable of delivering a good surface finish.
Hence, the correct option is (A).
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