Which type of backing is typically used for sanding discs?

The correct answer is C weight. In sanding discs, the backing refers to the material that provides support for the abrasive layer. C weight materials are typically made from a heavier paper that offers increased durability and tear resistance, making them suitable for the rigorous demands of sanding. This type of backing is ideal for applications where a strong backing is essential to withstand the forces encountered during sanding processes, particularly in automotive refinishing.

In contrast, other weights such as A, B, and J generally represent lighter backing materials. These lighter weight backings may not provide the same level of durability or stability needed for heavy sanding tasks, making them less appropriate for this specific application. C weight backings strike a good balance between flexibility and toughness, making them a preferred choice for professionals in the painting and refinishing industry.