Lesson Notes By Weeks and Term v4 - SHS 2

Lesson Video

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Performance objectives

• Identify different types of wood finishes.
• Understand why surface preparation is important.
• Learn the steps to apply a finish.
• Know the safety measures for finishing.

Lesson summary

In our communities, from the beautiful wooden doors of a chief's palace to the simple school desk we use every day, we see wooden items. Have you ever wondered why a new piece of furniture is smooth and shiny, while an old, neglected one is rough and dull? The secret is in the *finish*. Finishing is the final and one of the most important steps in woodwork. It protects the wood from damage, brings out its natural beauty, and makes it last longer. For any Ghanaian artisan or woodworker, mastering the art of finishing is key to creating high-quality products that can sell for a good price, both locally and internationally.

Lesson notes

This lesson is divided into three main parts: (A) The Importance of Wood Finishing, (B) Preparing the Surface, and (C) Types of Wood Finishes and Their Application. Part A: The Importance of Wood Finishing

Wood finishing is the process of applying a protective and/or decorative coating to a wooden surface. It is not just about making the wood look good; it serves several critical purposes: Protection: This is the primary reason. A good finish seals the wood, protecting it from: Moisture: Prevents the wood from swelling, warping, or rotting when it comes into contact with water. Think of a wooden kitchen cabinet. Sunlight (UV rays): Prevents the wood from fading or becoming brittle over time. Insects and Fungi: Seals pores in the wood, making it harder for pests like termites or borer beetles to attack. Wear and Tear: Protects against scratches, stains, and daily physical damage. A school desk with a strong varnish finish can withstand years of use. Aesthetics (Beauty): A finish can dramatically improve the appearance of an artefact. It can enhance the natural grain and colour of beautiful woods like Odum, Mahogany, or Sapele. It can add colour to plain woods like Wawa using stains or paints. It provides a smooth, pleasant feel to the touch. Hygiene and Cleanliness: A sealed and finished surface is non-porous. This means dirt, germs, and liquids cannot soak in, making the artefact much easier to clean and more hygienic. This is very important for items like dining tables and chopping boards. Increased Value: A well-finished product looks professional and durable. This increases its market value, allowing carpenters and furniture makers in Ghana to earn more for their work. Part B: The Preparation of Surfaces (The Foundation of a Good Finish)

Rule #1 in Woodwork: A perfect finish cannot hide a poorly prepared surface. 90% of a good finishing job is in the preparation.

Step-by-step Process: Planing and Scraping: For a rough-sawn piece of timber, a smoothing plane is first used to make the surface flat and remove saw marks. A cabinet scraper is then used to remove any fine marks left by the plane, resulting in a very smooth surface. Filing: For curved or shaped edges, files (like flat, round, or half-round files) are used to smooth and shape the wood where a plane cannot reach. Sanding (Glass Papering): This is the most common and crucial step. Sandpaper Grits: Sandpaper comes in different "grits" (roughness). You must work from a lower number (coarser) to a higher number (finer). For example, start with P80 grit, then move to P120, and finish with P180 or P220. Technique: ALWAYS sand in the direction of the wood grain. Sanding across the grain will create ugly scratches that will show up clearly after the finish is applied. Wrap the sandpaper around a smooth wooden block for flat surfaces to ensure even pressure. Filling: If there are any nail holes, cracks, or small knots, they should be filled with wood filler or putty. Choose a filler that matches the colour of the wood. After the filler dries, it must be sanded smooth. Staining or Bleaching (Optional): Staining: If you want to change the colour of the wood (e.g., make Wawa look like Mahogany), a stain is applied *before* the protective topcoat. Bleaching: If you want to lighten the natural colour of the wood, a wood bleach is used. Final Cleaning (Dust Removal): After the final sanding, all dust must be removed from the surface. Use a dry brush, a vacuum, or a tack cloth (a slightly sticky cloth that picks up fine dust). Wiping with a cloth lightly dampened with methylated spirit also works well. The surface must be perfectly clean and dry before any finish is applied. Part C: Types of Wood Finishes

Evaluation guide

• Apply an appropriate finish to an artefact
• Critical Thinking and Talk for Learning Approaches: Learners think
• pair share to passionately identify and describe the tools and materials for
• preparation of surfaces of artefacts (cleaning -up).