Finning

• Sharp metal fins that appear perpendicular to the surface of the casting and vary in severity from superficial (about 1 mm high) to heavy (several mm high)

• Indicates that a portion of the shell has cracked during shelling or dewax and metal fills the crack

  • Superficial finning typically occurs when the primary shell coat has cracked and is especially prevalent on round parts due to hoop stress

  • Heavy finning typically occurs when the entire ceramic shell has cracked is especially prevalent on edges

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