What is the first step in trimming master casts?

The first step in trimming master casts is to soak the master cast in clear slurry water. This technique helps to soften the surface of the cast, making it easier to trim and shape accurately. Soaking in slurry water can prevent the cast from being damaged during the trimming process by reducing the abrasion of the trimming tools on the hard stone surface. Additionally, this step ensures that any debris or particles on the cast are loosened and easily removed, which is vital for achieving a clean and precise trim. Proper preparation of the cast sets the foundation for successful trimming and overall quality in the denture fabrication process.