Question

In shell moulding, the binder used to hold the sand grains together is:

• A. Clay
• B. Sodium silicate
• C. Thermoplastic resin
• D. Silica gel

Hint:

Remember: Shell moulding uses a heated metal pattern and thermosetting resin to create a hardened shell, making it ideal for precision casting.

Answer 1

The Correct Option is C

In the shell moulding process, a mixture of fine sand and a thermoplastic resin (commonly phenol-formaldehyde) is used.
The mixture is heated in a metal pattern which causes the resin to cure and form a rigid shell around the sand particles.
This shell serves as the mould and provides high dimensional accuracy and good surface finish in the final cast product.