Product Design (Timber's)

Overview of Timbers

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Timber - Groups

- Timber or wood can be divided into 3 groups -

- Softwoods –Pines, spruces (xmas tree) Larches (spinney/tennis courts) Firs, Yew.

- Hardwoods - Oak, ash, beech, walnut, birch cherry, (Europe/GB) Teak, mahogany, walnut (exotic/hot countries)

- Manufactured boards – man made, chipboard, MDF, plywood, hardboard.

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Softwoods

Softwoods

- Used mainly in construction industry.

- Generally softer than hardwoods but hard enough for roofs, stairs, frames, sheds etc.

- Quick growing trees so timber is cheaper than hardwoods.

- Most hardwoods are x2 of softwoods some x3.

- Softwoods grow mainly in temperate & cold climates – huge forests in Russia, Scandinavia & Canada.

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Hardwoods

Hardwoods 

- Grow in temperate & hot countries. 

- Used for all types of furniture, church interiors, construction, musical instruments, ships interiors, veneers.

- More expensive than softwoods, some are extremely expensive( rarer varieties).

- Huge range of varieties.

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Manufactured Board

Manufactured boards -

- Some are relatively cheap - chip, MDF & hardboard about the same as softwoods.

- Useful for large areas, doors, panels, backs, table tops, work surfaces etc.

- Generally stable materials.

- Often veneered with wood or plastic laminates – a relatively cheap wood enhanced to make it look expensive.

- Edges often need lipping.

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Types of Manufactured Boards

Manufactured Boards –

Chipboard – Made of wood chips glued together under pressurenot waterproof.

MDF – made of glued wood fibresnot waterproof.

Both can be veneered.

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Manufactured Board - Plywood

Plywood –

- Built up in layers with adjacent layers at 90° thus preventing splitting making it about x 20 stronger than ordinary timber.

- Can be veneered.

- Marine ply is waterproof.

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Veneered Wood

Veneers -

- Thin layer of wood, often an expensive, exotic wood, peeled off a log (toilet roll).

- Used to enhance the appearance of manufactured boards to give upgraded/ expensive appearance.

- Rotary Cut Veneers:  Quickest - Most veneer – Most economical – Least waste.

- Slice Cut Veneers: Best grain patterns – Matching patterns – most waste – more expensive. 

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Strength of Wood

- Knots in wood can weaken the structure and cause irregular grain making it difficult to work.

- Wood splits along the grain.

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Defects of Wood

- Defects lower the value of timber. 

- Distortion & splits occur mainly because of uncontrolled drying out of the wood. 

- Timber will shrink when it dries & vice versa.

- Knots are natural defects.

- Warping, Bowing, Twisting, Cupping all occur on woods and affect the properties of Wood.

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Structure of Timber

Conversion -

- Changing a log into usable timber:

- Slab sawing is the quickest & easiest method.

- Quarter/Radial sawing gives better quality timber, but is more expensive because it takes longer & there is more waste.

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Laminated Flooring

Laminate Flooring –

- A laminate is made up in layers.

- Kitchen/computer worktops are made of melamine.

- Formaldehyde then glued to a manufactured board base.

- Giving an enhanced, hardwearing material.

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