Dampness
The requisite degree of dampness in moulding-sand is a matter of great importance to the moulder. If too moist, steam is generated by the hot metal quicker than the vents will allow it to escape, and scabs will inevitably ensue. If not damp enough, it lacks consistency and fails to preserve its shape in the mould, being easily disturbed during the ordinary operations of moulding, and yielding too readily to the abrading action of the molten metal. See VENTING; SCABBED CASTINGS.