Question

Which of the following items is used for trapping impurities from entering the mould?

(a) Facing sand

(b) Core

(c) Skim bob

(d) Pouring basin

This question was posed to me in class test.

The above asked question is from Aspiration Effect in portion Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

Answer 1

The correct option is (c) Skim bob

For explanation: Skim bob is a trap placed in a horizontal gate to prevent heavier and lighter impurities from entering the mould. It removes the dross if not strained by strainer and the sand also. Skim bob appears like as shown in the below figure.