Finishing

Finishing refers to processes that alter the surface of a material to improve appearance, protect against wear, or impart specific properties. Finishes are commonly applied at the end of manufacturing or construction, and they may affect color, texture, hardness, chemical resistance, or moisture interaction. Finishing can be mechanical, chemical, or thermal, and often combines several steps.

Mechanical finishing includes sanding, polishing, buffing, and grinding to create or refine surface texture and prepare the substrate for coatings. Chemical finishing involves applying coatings or treating the surface through chemical reactions, such as staining, varnishing, painting, electroplating, anodizing, passivation, or chemical sealing. Thermal finishing includes heat treatments or controlled coloration such as patination, with some processes using heat to harden or alter a surface.

Wood finishing is a common example, using oils, waxes, shellac, varnishes, polyurethane, and stains to enhance grain and protect the wood. Metal finishing includes plating (electroplating or electroless plating), anodizing, galvanizing, and various surface treatments to improve corrosion resistance, wear, or aesthetics. Plastics and composites may be sealed, painted, or coated with specialized sealants. Concrete often receives sealers or protective coatings to reduce moisture absorption and wear.

Quality and selection depend on substrate, environment, aesthetics, and maintenance. Finishes are evaluated for properties such as durability, gloss, color fastness, and surface smoothness. Environmental and safety considerations include solvent emissions, volatile organic compounds, and waste disposal, guiding sustainable finishing practices.