Wood finishing

Worker Applying a Wood Finish

Large open ‘pores’ in a Eucalyptus sieberi

Pore distribution in beech

SEM of 120 grit aluminum oxide paper

SEM of 180 grit aluminum oxide paper

Yellow birch after sanding

Wood finishing refers to the process of refining or protecting a wooden surface, especially in the production of furniture where it represents the final step of the manufacturing process. Finishing is a means to enhance the appearance and durability of wood, and can involve various techniques and materials.

Types of Finishes

Wood finishes can be categorized into several types, including but not limited to:

• Varnish: A transparent, hard protective finish or film primarily used in wood finishing but also for other materials. Varnishes are traditionally a combination of a drying oil, a resin, and a thinner or solvent.
• Lacquer: A clear or coloured wood finish that dries by solvent evaporation and often a curing process that produces a hard, durable finish. Lacquers can be applied by spraying or brushing.
• Oil-based finishes: These penetrate the wood and harden to form a protective coating. Examples include linseed oil, tung oil, and Danish oil. They are known for enhancing the wood's grain and natural beauty.
• Wax: Used to polish over another finish or as a standalone finish, wax provides a soft sheen and a smooth feel. It's less durable than other finishes and requires more frequent reapplication.
• Shellac: A resin secreted by the female lac bug, dissolved in alcohol to create a wood finish. Shellac can be used as a brush-on colorant, food glaze, and wood finish.
• Water-based finishes: These finishes are low-odor, dry quickly, and clean up easily with water. They're durable and can be clear or pigmented.

Application Techniques

The application of wood finishes can vary depending on the type of finish and the desired outcome. Common techniques include:

• Brushing: A traditional method suitable for many types of finishes. It requires a quality brush and technique to avoid brush marks.
• Spraying: Offers a smooth finish and is faster than brushing. It's ideal for lacquers and varnishes but requires specialized equipment.
• Wiping: An easy method for applying oil-based finishes. It involves applying the finish with a cloth or sponge, then wiping off the excess.
• Dipping: Used in industrial settings, where pieces are completely dipped in the finish, then hung to dry.

Preparation and Sanding

Proper preparation is crucial for achieving a quality finish. This typically involves sanding the wood to a smooth surface, starting with coarse-grit sandpaper and progressing to finer grits. Sanding removes imperfections and ensures that the finish will adhere properly and look even.

Safety and Environmental Considerations

Working with wood finishes requires attention to safety and environmental considerations. Many finishes emit volatile organic compounds (VOCs) and require adequate ventilation. Personal protective equipment (PPE), such as gloves and respirators, is also recommended. The disposal of finishes and solvents must comply with local environmental regulations to minimize their impact on the environment.

Conclusion

Wood finishing enhances the beauty and durability of wood products. The choice of finish and application method depends on the desired aesthetic, the use of the item, and the type of wood. Proper preparation, application, and safety practices ensure a successful and lasting finish. Template:Craft-stub