Introduction to Natural and Manufactured Timbers

Welcome! In this chapter, we are going to explore one of the most versatile and widely used materials in the world: timber. Whether you are looking at a traditional wooden toy or a piece of flat-pack furniture, understanding where wood comes from and how it behaves is vital for any designer.

We divide timbers into two main "natural" categories—Hardwoods and Softwoods—and a third category called Manufactured Boards, which are man-made. Let’s dive in!

1. Natural Timbers: Hardwoods vs. Softwoods

The names can be a bit confusing! "Hardwood" doesn't always mean the wood is hard, and "Softwood" doesn't always mean it's soft. The difference actually comes from the type of tree and how it reproduces.

Hardwoods

Hardwoods come from broad-leaved trees (deciduous) that usually lose their leaves in winter. They grow slowly, which often makes them denser and more expensive.

  • Oak: Very strong, heavy, and durable. Often used for high-quality furniture.
  • Ash: Flexible and good at absorbing shocks. Used for tool handles and sports equipment.
  • Beech: A hard, tough wood that doesn't smell or taste of anything—perfect for kitchen products and children’s toys.
  • Mahogany: Known for its reddish-brown color and beauty. Used for expensive furniture and veneers.
  • Balsa: The big exception! Even though it’s a hardwood, it is incredibly soft and lightweight. It’s perfect for model making.

Softwoods

Softwoods come from coniferous trees (evergreens with needles and cones). They grow much faster than hardwoods, which generally makes them cheaper and more sustainable.

  • Pine: Very common, easy to work with, and relatively cheap. You’ll see it used in construction and simple furniture.
  • Spruce: A creamy-white wood that is lightweight but has a good strength-to-weight ratio.
  • Larch: More durable and resistant to rot than other softwoods, making it great for outdoor use like garden fencing or cladding.

Quick Tip: Don't worry if you forget which is which! Just remember that most softwoods have needles and cones, while hardwoods have broad leaves.

2. Manufactured Boards

What happens if we need a very wide, flat piece of wood that won't warp or twist? Natural timber isn't always big enough. This is where manufactured boards come in. These are made by gluing wood fibers, chips, or layers together.

  • Plywood: Made by gluing thin layers (veneers) of wood at 90-degree angles to each other. This makes it incredibly strong in all directions.
  • Medium Density Fibreboard (MDF): Made from tiny wood dust particles glued together under pressure. It has a very smooth surface, making it easy to paint.
  • Chipboard: Made from small chips of wood compressed and glued together. It’s often used in flat-pack furniture with a plastic laminate on top because it’s very cheap but not very strong on its own.

Key Takeaway: Manufactured boards allow us to use "waste" wood and create large, stable sheets that are often cheaper than solid timber.

3. Sources and Origins: From Tree to Timber

How does a tree in a forest become a plank in a workshop? There are two main stages you need to know: Conversion and Seasoning.

Conversion

This is the process of sawing the logs into usable planks. Designers choose different ways of sawing depending on the grain pattern they want and how much money they want to spend.

Seasoning

When a tree is first cut down, it is full of water (moisture). If we used it immediately, the wood would shrink, crack, or warp as it dried out. Seasoning is the process of drying the wood to a usable level.

  • Air Seasoning: Planks are stacked outside with gaps for air to circulate. It's cheap but slow.
  • Kiln Seasoning: Planks are put in a giant oven (a kiln). It is much faster and kills insects, but it is more expensive.

Did you know? Reducing the moisture content makes the timber stronger, more stable, and less likely to decay!

4. Working with Timber: Tools and Components

As a designer, you need to know how to shape and join timber. Here are the specific techniques mentioned in your syllabus:

Shaping Techniques

  • Cutting: Using saws to get the basic shape.
  • Drilling: Creating holes for fixings.
  • Chiseling: Removing small sections of wood, often for joints.
  • Planing: Shaving off thin layers to make an edge straight or smooth.
  • Sanding: Using abrasives to get a smooth finish.
  • Routing: Using a machine (router) to cut slots or decorative edges.
  • Turning: Using a lathe to create cylindrical shapes (like a table leg or a bowl).

Standard Components

Instead of making everything from scratch, we use standard components to save time and money:

  • Woodscrews: Used to join pieces of wood together.
  • Hinges: Allow doors or lids to open and close.
  • Knock-down (KD) fittings: These allow furniture to be assembled and disassembled easily (think of the connectors in IKEA furniture).

5. Quality Control and Finishes

Quality Control (QC)

To make sure products are made correctly, manufacturers use dimensional accuracy. A common tool for this is a go/no-go fixture. This is a template that the part must fit into. If it fits perfectly, it’s a "go"; if it’s too big or small, it’s a "no-go" and is rejected.

Surface Treatments

Wood is a natural material that can rot or look dull. We apply finishes for Aesthetics (to look good) and Function (to protect it).

  • Painting: Hides the grain and adds color.
  • Varnishing: A clear, hard coating that shows the grain but protects the wood from water.
  • Preserving: Essential for outdoor wood (like Larch or Pine) to stop it from rotting or being eaten by insects.

6. Ecological and Social Footprint

Using wood has a big impact on our planet. The most significant issue is Deforestation. When trees are cut down faster than they are replanted, it destroys habitats and increases carbon dioxide in the atmosphere.

Sustainable Design: Designers should look for timbers with the FSC (Forest Stewardship Council) logo, which proves the wood comes from a forest where new trees are planted to replace the ones cut down.

The 6 Rs: Remember to apply these to timber!
1. Reduce: Use less wood by nesting parts carefully.
2. Reuse: Can an old pallet be turned into a chair?
3. Recycle: Chipboard is often made from recycled wood.
4. Repair: Fixing a broken chair rather than throwing it away.
5. Refuse: Don't use endangered hardwoods like some types of Mahogany.
6. Rethink: Is there a more sustainable way to make this?

Quick Review: Key Terms

Hardwood: From broad-leaved trees (e.g., Oak, Beech).

Softwood: From coniferous trees (e.g., Pine, Spruce).

Seasoning: Drying wood to prevent warping.

Plywood: A strong manufactured board made of layers glued at 90 degrees.

Deforestation: The environmental cost of over-harvesting timber.