Mozart Trimming Knife Replacement Blades. 5 pack of Mozart Trimming Knife Replacement Blades in stock for fast shipping. Includes a pack of five replacement blades for the Mozart Skiving Knife used for trimming excess heat welding rod flush at the seam. These replaceable blades are flexible to eliminate gouging of high spots which can occur with quarter moon knives. They also eliminate difficult resharpening of quarter moon knives.