During lost-wax casting, which statement about the burnout stage is correct?

During lost-wax casting, which statement about the burnout stage is correct?

• A. It takes place after casting to refine the metal surface.
• B. It uses heat to remove wax pattern from the investment, leaving a hollow mold.
• C. It is optional if the wax pattern is simple.
• D. It strengthens the wax pattern before investment.

Answer: (B)

The burnout stage uses heat to remove the wax pattern from the investment, leaving a hollow mold. By heating, the wax melts and vaporizes and escapes through the porous investment, creating a cavity that exactly mirrors the wax pattern. This hollow mold is then ready to receive molten metal. Burnout must be done before pouring to ensure there are no wax residues that could cause defects or gas pockets in the final casting. It's not about refining the metal surface or strengthening wax—those happen in other steps. And burnout is not optional; without it, the mold cannot properly form the metal piece.

The burnout stage uses heat to remove the wax pattern from the investment, leaving a hollow mold. By heating, the wax melts and vaporizes and escapes through the porous investment, creating a cavity that exactly mirrors the wax pattern. This hollow mold is then ready to receive molten metal. Burnout must be done before pouring to ensure there are no wax residues that could cause defects or gas pockets in the final casting. It's not about refining the metal surface or strengthening wax—those happen in other steps. And burnout is not optional; without it, the mold cannot properly form the metal piece.