Question

Why should the moulding sand be porous?

(a) For gases to enter

(b) For gases to escape

(c) For water to enter

(d) For water to escape

This question was addressed to me during an internship interview.

My question is from Properties of Molding Sands topic in section Molding and Core Sands of Casting-Forming-Welding I

Answer 1

Correct answer is (b) For gases to escape

To explain: A moulding sand is the one in which, the sand is known to have holes in it and also it is known for holding some amount of moisture content. A moulding should be having pores and should be permeable so that the gases have a free path for escaping.