Choosing the right sanding disc involves several factors to ensure optimal results and efficiency for your project. First, consider the grit size. Coarse grits (e.g., 40-80) are best for rapid material removal, shaping, or removing heavy coatings like paint or rust. Medium grits (e.g., 100-150) are versatile for general sanding, smoothing imperfections, and preparing surfaces for finishes. Fine grits (e.g., 180-220) are ideal for final smoothing before staining or painting, while very fine grits (240+) are for ultra-smooth finishes or between-coat sanding.
Next, consider the abrasive material. Aluminum oxide is a common and economical choice, suitable for wood, metal, and plastic. Zirconia alumina is tougher and longer-lasting, excellent for aggressive removal on hardwoods and metals. Ceramic abrasives are the most durable and aggressive, perfect for demanding applications on tough materials. Silicon carbide is sharp and brittle, making it good for non-ferrous metals, fiberglass, and wet sanding.
The disc's backing material also matters. Paper backings are common and cost-effective, but can tear. Cloth backings are more durable and flexible, suitable for more aggressive sanding. Film backings offer superior uniformity and tear resistance, great for fine finishing.
Finally, consider the disc's attachment method (hook-and-loop, PSA/pressure sensitive adhesive), and any dust extraction hole patterns if using a sander with dust collection. Matching these to your tool is crucial.