Parting
The joint or point of separation in moulds composed of two or more sections. A suitably prepared surface at some portion of a mould that will permit one part to be separated from another without fracturing the sand structure. For a separation of plain moulds contained in a cope and nowel, the sand-joint is made smooth and sprinkled all over with dry parting-sand, which prevents any portion of the sand rammed over it in the cope from adhering thereto. But should any portion of such joint assume a vertical or other form than the horizontal, the parting-sand must be moistened before it will adhere to the joint surface; especially is this the case with drawbacks, which separate in a vertical position. In either of the latter-mentioned cases paper may be substituted for the moistened parting-sand. See DRAWBACKS; PAPER-PARTING; PARTING-SAND.
Parting-sand is sand specially adapted to the prevention of joint, or separating surfaces amalgamating when they have been rammed against each other. Beach and river sands are eminently adapted for this purpose, as all clayey compounds have, by the action of the water, been washed out. New fine free sand, well burnt to eliminate every trace of clay, is adapted for use as a parting-sand; and it may be said that the beach and river sands have their parting qualities enhanced by burning, the burnt cores from the castings being always preferred to the new sands. See PARTING; JOINT; etc.