A ridge of excess metal that can occur when molten metal enters cracks in the refractory mold or in the core. Flashing most often rises perpendicular to the inner or outer wall of bronze although a gap in consecutive layers of the mold material may result in thin flanges of excess bronze that spread parallel to the metal wall. This type of casting flaw can appear on the cast’s internal and external surfaces (respectively called core flashing and mold flashing) and are more often removed from the latter during fettling. Flashing may also occur along seam lines of an ill-fitted piece mold.
Note: The term flashing is also used to describe a seam line. However, to avoid confusion it is recommended that it be used specifically in connection with casting defects.
