Overview
This lesson covers the main types of timbers (hardwoods, softwoods, manufactured timbers) and their properties, focusing on their definitions, characteristics, and common uses.
Hardwoods
- Hardwoods come from deciduous trees with broad leaves and slow growth (≈60 years).
- They are often expensive and found in tropical or temperate climates.
- Oak: moderate brown, tough, durable, attractive grain, used for furniture but expensive and hard to work with.
- Mahogany: dark red, close grain, easy to cut and polish, used for high-quality furniture but can cause skin/breathing issues.
- Beech: slight pink, tough, smooth, not moisture-resistant, used for toys and cooking tools.
- Balsa: pale, very soft and lightweight, easy to cut, used for model making but too weak for most products.
Softwoods
- Softwoods come from fast-growing coniferous trees (often with needle-like leaves).
- They grow in colder (alpine) regions and are generally cheaper.
- Pine: pale, durable, easy to work, cheap, can splinter, used for construction, furniture, and doors.
- Cedar: lightweight, pale, water/fungi resistant, not as strong as pine, used for outdoor furniture and fences.
Manufactured Timbers
- Made from leftover wood (sawdust, chippings) pressed into large sheets.
- Plywood: layers of veneer glued at 90° for strength, stable, looks like wood, but expensive and edges can be rough.
- MDF (Medium Density Fiberboard): made from wood dust/fibers with glue, smooth, easy to work, but absorbs moisture and is weak, used for cheap furniture.
Timber Properties
- Hardness: resistance to cutting and scratching; oak is hard, balsa is soft.
- Toughness: ability to withstand being hit without breaking; timber can dent but not break.
- Durability: ability to last over time; dry/treated timbers are durable, while wet wood rots quickly.
Key Terms & Definitions
- Hardwood — Timber from slow-growing deciduous trees.
- Softwood — Timber from fast-growing coniferous trees.
- Manufactured Timber — Engineered sheets made from wood waste (e.g., plywood, MDF).
- Hardness — Resistance to cutting/scratching.
- Toughness — Ability to absorb impact without breaking.
- Durability — Ability to resist decay and last over time.
Action Items / Next Steps
- Review properties and uses of each timber type.
- Compare advantages/disadvantages for exam preparation.