Wetsanding

Wetsanding is a finishing technique in which an abrasive material is used on a surface with a continuous flow of water or other lubricant. The water cools the workpiece, carries away debris, and reduces the amount of dust generated. This combination allows finer finishes with less heat buildup, making wetsanding common in automotive refinishing, woodworking, boat maintenance, and model making.

Process and materials: Waterproof abrasive papers or sanding sponges are used with a damp surface, often on a sanding block or flexible pad. Water or a mild lubricant is applied constantly to flush away grit. Grits progress from coarse to fine, e.g., 400–600 to flatten irregularities, then 800–2000 for finishing, depending on material and desired gloss. In automotive work, wetsanding may occur between coats or as a final finish before polishing.

Techniques and tools: Wet sanding can be done by hand or with a rubber block or oil-free orbital sander rated for wet use. Keep the surface constantly wet and rinse the paper frequently to avoid clogging. The procedure often ends with polishing compounds and a clean, dry inspection to ensure uniformity. Common hazards include splash hazards, slippery surfaces, and potential water intrusion into joints or electronics.

Advantages and limitations: Wet sanding reduces dust, cools the surface for finish integrity, and enables very fine finishes. It is slower than dry sanding and requires ongoing cleanup and drying time. It can introduce water into assemblies if not sealed, so care is needed around joints and edges.