Veining is caused by the expansion of silica sand during casting This photo shows some typical effects of veining on a disc brake casting
PUNB technology has not normally been chosen for molding operations producing largescale iron castings because its mixedsand working life mdash the period during which the bindermixedsand can be packed rammed vibrated etc before it begins to cure mdash has been relatively short
At one time environmental benefits were practically the only benefit of inorganic binders However through extensive RampD efforts superior inorganics have emerged allowing for higher performance that exceeds even that of cold box technology