Lesson Notes By Weeks and Term v4 - SHS 1

Lesson Video

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Performance objectives

• Define manufactured boards and solid wood.
• Identify different types of manufactured boards.
• Discuss the advantages of manufactured boards over solid wood.
• Analyse the disadvantages of manufactured boards.

Lesson summary

In Ghana, our woodwork industry has a rich history of using beautiful solid woods like Odum, Wawa, and Mahogany to create strong, lasting furniture. However, as you look around your home, school, or local furniture shops in places like Sokoban (Kumasi) or Anloga Junction (Accra), you will see many items made from materials that look like wood but are actually different. These are called manufactured boards. This lesson will explore what these modern materials are, how they are made, and why a carpenter might choose to use them instead of traditional solid wood.

Lesson notes

This section contains all the core information needed for the lesson. 2.1. Defining the Core Materials

a) Solid Wood: This is natural wood that has been cut directly from the trunk of a tree. It is a single, solid piece of timber. After a tree is felled, it is milled into planks or boards of various sizes. Examples in Ghana: Odum (Iroko), Sapele, Wawa, Mahogany, Ofram. Key Characteristic: It has a natural grain pattern, knots, and other features that make each piece unique. It is strong along the grain but can be weaker across the grain. It also tends to expand, contract, warp, or twist with changes in humidity.

b) Manufactured Boards (or Engineered Wood): These are man-made boards produced by binding together wood strands, particles, fibres, or thin sheets of wood (veneers) with adhesives under heat and pressure. They are designed to have specific properties that often overcome the limitations of solid wood. Analogy: Think of solid wood as a whole piece of cassava. A manufactured board is like *gari* or *agbelikaklo* – it's made *from* cassava, but it has been processed and reformed into a new, stable, and useful product. Common Feature: They are usually sold in large, standard-sized sheets (e.g., 4 feet by 8 feet, or 1220mm x 2440mm). 2.2. Common Types of Manufactured Boards in Ghana Plywood: What it is: Made by gluing together several thin layers of wood veneer (called 'plies'). Each layer's grain is placed at a 90-degree angle (right angle) to the layer below it. How it's made: Logs are peeled into long, thin sheets (veneers). These veneers are dried, glued, and stacked with alternating grain directions. The stack is then pressed under high heat to form a strong, stable board. Characteristics: Very strong in all directions due to the cross-graining. Resists warping, shrinking, and cracking. Can have a decorative top veneer from woods like Sapele or be plain. Common Uses in Ghana: Roofing underlayment (the board your roofing sheets are nailed to), formwork for casting concrete pillars, furniture carcasses, doors, and speaker boxes. Medium Density Fibreboard (MDF): What it is: Made from very fine wood fibres (almost like wood dust) mixed with wax and resin adhesive. How it's made: Wood chips are broken down into fine fibres in a defibrator. These fibres are mixed with glue, formed into a mat, and pressed under high temperature and pressure. Characteristics: Very dense, smooth, and flat surface with no grain pattern. Excellent for painting, laminating, or applying veneers. Easy to machine and cut into detailed shapes. It swells and falls apart very quickly when it gets wet, unless it's a special moisture-resistant type. Common Uses in Ghana: Kitchen cabinets, wardrobes, office furniture, display shelves, and decorative mouldings. Particleboard (often called Chipboard): What it is: Made from small wood particles, chips, or even sawdust, mixed with a synthetic resin or another binder. How it's made: Wood chips and particles are mixed with glue and pressed together under heat to form a board. It is less dense than MDF. Characteristics: The cheapest of the manufactured boards. Not very strong and cannot hold screws well unless special fittings are used. Very susceptible to moisture damage; it swells and crumbles easily. Often covered with a thin plastic laminate or wood veneer to improve its appearance and durability. Common Uses in Ghana: Low-cost furniture (e.g., flat-pack TV stands, cheap bookshelves), internal core for some doors, and substrate for countertops. 2.3. Comparing Manufactured Boards and Solid Wood

Here is a detailed comparison which directly addresses the lesson's indicator.

Evaluation guide

• Discuss the advantages of manufactured boards over solid wood.
• Critical Thinking and Talk for Learning Approaches: Guide learners through whole class
• session to brainstorm the meaning of manufactured boards (Engineered wood) with open- mindedness
• Group work/Collaborative Learning