In SMC repair, what type of material is used for reinforcement?

The correct choice is fiberglass reinforcing material. In the repair of Sheet Molding Compound (SMC), fiberglass is commonly used because it provides significant strength and rigidity to the structure while remaining lightweight. This combination makes fiberglass an ideal reinforcement material for SMC, as it enhances the durability and performance of the repaired area without substantially adding weight.

Fiberglass offers excellent resistance to environmental factors and chemicals, which is crucial in automotive applications where components may be exposed to various conditions. Additionally, when properly applied, fiberglass can create a strong bond with SMC surfaces, ensuring that repairs are effective and long-lasting.

Other materials such as metal sheets, plastic compounds, and wood panels are not typically utilized in the same capacity for SMC repairs, as they do not provide the same compatibility, structural enhancements, or benefits that fiberglass does. Thus, fiberglass stands out as the optimal choice for reinforcing SMC in damage repair scenarios.