What must be dropped into the mold prior to adding the welding material?

• A. The Metal Disk
• B. A Ceramic Disk
• C. A Sealing Cap
• D. A Paper Towel

Answer: (A)

In this situation, mold preparation for welding relies on using a material that can act as a stable, heat-tolerant backing inside the mold. The metal disk fits that role because it can withstand the high temperatures of the welding material and provide a hard, smooth surface that helps shape and position the weld as it is deposited. Dropping the metal disk into the mold before adding the welding material creates a solid base that prevents molten material from sticking to or distorting areas of the mold, and it helps produce a clean, well-defined weld boundary as it cools. A ceramic disk would be prone to cracking under heat, and a sealing cap or paper towel would not endure the process and could contaminate or burn, offering no proper backing. So the metal disk is the right choice because it remains intact during welding and supports a precise, clean weld surface.