Question

Which of the following is not a defect if permeability is not enough?

(a) Brittleness

(b) Gas holes

(c) Mould blast

(d) Surface blows

The question was posed to me in examination.

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

Answer 1

Right answer is (a) Brittleness

The best I can explain: If the permeability or the porosity is less or the permeability is found to be inadequate or the porosity is found to be absent, then brittleness is not the defect it has, but it may have, gas holes or mould blasts or surface blows.