Material for cast includes Pinter’s second column (8)
I believe the answer is:
pilaster
'column' is the definition.
(pilaster is a kind of column)
'material for cast includes pinter's second' is the wordplay.
'material for cast' becomes 'plaster' (material for a plaster cast).
'includes' indicates putting letters inside.
'pinter's second' becomes 'i' (2nd letter of 'pinter').
'plaster' enclosing 'i' is 'PILASTER'.
(Other definitions for pilaster that I've seen before include "Square column" , "Rectangular column support projecting slightly from a wall" , "Piles tar into a form of column" , "Rectangular column projected from wall" , "Decorative column standing out from the fa?ade of a building" .)