Why is a block used with hand sanding?

A block is used with hand sanding primarily to ensure an even surface and to prevent the sandpaper from leaving impressions on the surface being sanded. When using a sanding block, the flat surface helps distribute pressure evenly, which allows for a more uniform sanding action that reduces the likelihood of creating dips or irregularities. This technique is especially important when working on flat surfaces, as it helps achieve a smoother and more professional finish.

Using a sanding block also improves control during the sanding process, ensuring that the sandpaper maintains contact with the surface at the correct angle and pressure. Without a block, the sandpaper can easily conform to any irregularities in the surface, which can lead to uneven sanding. Therefore, using a sanding block is essential for achieving high-quality results in painting and refinishing work.