Composite wood is a manufactured product made from particles of timber of different sizes and shapes obtained from a variety of sources and moulded into shape using resin or glue.
The price, versatility and physical properties of these materials have revolutionised the woodworking and manufacturing industries.
History
There is debate over what constitutes composite and therefore when was the first and what form did it take. As far ago as 3400BC, wood was glued together at different angles to form a rudimentary plywood. In 1797, a British engineer patented a type of wood laminate, and in 1930s Germany, a form of particleboard was used.
However, a definite turning point occurred in Milan in 1960 where a mixture of wood and plastic or wood plastic composite (WPC) was patented and marketed under the trademark Plastic-Wood. Since then, many types of composite woods have been developed, here are a few of the most useful and widely used.
Types of composite wood
Particleboard
Also known as chipboard, this material is probably the most familiar type of composite wood, especially to those of us around at the time of the rise of flat-pack furniture design in the 80s and 90s. Even with the advent of more modern materials, particle board is still widely used for its strength and cost-effectiveness.
Flakes or chips of wood are collected as by-products of other processes, or to make use of inferior wood that would otherwise go to waste, and mixed with resin to form a desired shape, usually a flat sheet. More recent developments have seen graded density or 3 layer chipboard, where smaller particles are used towards the surface which adds durability and tensile strength.
Particleboard sheets are often coated or laminated to improve their aesthetic look and resistance to wear and tear, they are affordable and versatile but less durable than other composite woods.
Medium-density fibreboard
Medium-density fibreboard or MDF and its less talked about counterpart, high-density fibreboard/HDF/hardboard have been used extensively for over 40 years. The difference between the two is basically the pressure under which they are manufactured.
Timber, recycled wood or the waste from other processes that use wood, is passed through a chipping stage then the small chips are collected and passed to the next stage. The resultant product is then heated and ground to produce individual fibres which are first coated by a thin layer of wax. Resin is then added in approximately 9 to 1 ratio, fibre/resin then the whole thing is compressed to produce the required density.
Medium-density fibreboard is relatively soft and easy to work with while retaining a fairly robust structure once assembled into the furniture [link to furniture design article]. High-density fiberboard is much harder and gives a smooth, dense surface, making it ideal for painting and finishing so it is often used for flooring, doors, and furniture components.
Oriented strand board
Oriented strand board or OSB has been around since the 1960s and was first used in California, USA. Large flat chips or strands of wood are compressed with resin in specific orientations to form a compressed sheet. OSB is known for its structural strength, making it suitable for sheathing, roofing and subflooring.
Due to its unsightly appearance, OSB is very much a behind-the-scenes player. Also due to the way the strands overlap, the board has favorable mechanical properties in the construction industry where its strength can be utilised but it also can be covered and out of sight.
Plywood
Plywood is formed using several layers (also known as plies, hence the term ply-wood) that are glued together in alternate orientations to form a very strong sheet. The grain of a piece of timber has an inherent weakness that runs with the grain, if a piece of wood ever breaks, it is generally with, rather than across, the grain.
Since plywood is constructed from multiple layers of veneer glued together in alternating grain directions, it has excellent strength and stability, making it ideal for construction and furniture. It is also available in various grades, depending on the quality and thickness of the veneers.
Environmental considerations
While composite wood is more sustainable than solid wood, it’s important to consider its environmental impact, for example, the production process involves chemicals and energy consumption.
Responsible manufacturers prioritize eco-friendly practices, such as using recycled materials and reducing emissions, and encourage this process by buying from responsible sources.
For example, when choosing composite wood products, look for certifications like the Forest Stewardship Council (FSC) to ensure the materials that you are buying, come from sustainably managed forests.
