MDF wood, or medium density fiberboard, is a composite wood made by gluing together wood fibres with heat, resin and pressure. The wood is used in a variety of construction and industrial processes and is considered a reliable and cheaper alternative to solid wood.
Manufacture and History
Manufacturers make MDF wood from wood fibre, or chips, that they bond with resin and pressurise in refineries to reduce the overall bulk density of the finished product. Commercial production of MDF began in United States in the 1960s, based on the concept and design of hardboard, another similarly engineered wood product.
According to Jay A. Johnson and W. Ramsay Smith in the book "Forest Products Trade: Market Trends and Technical Developments," the density of MDF wood ranges from 0.64 grams per cubic centimetre to 0.80 grams per cubic centimetre. Medium density fiberboard has a specific gravity ranging from 0.5 to 0.88.
Various grades and types of MDF wood are available, including moisture resistant, fire retardant (or resistant) and nuclear resistant MDF wood. Medium density fiberboard is also classified into laminate, particle and fibre MDF wood. MDF comes in sheets commonly measuring 4 feet (48 inches) by 8 feet (96 inches) and 5 feet (60 inches) by 8 feet (96 inches). Thicknesses vary from 1/2 inch to 3/4 inch and 1 inch.
Builders use MDF wood to make logos and lettering; display cabinets; casework and boxes; furniture; exterior cladding; exhibition plinths; drawer fronts and cabinet doors; and internal cabinet frames.
MDF wood is structurally consistent, fine and durable. Unlike solid lumber, the density of medium density fiberboard remains consistent throughout its thickness. The wood readily takes up a number of finishes, including water- and oil-based paints, varnishes and polish. MDF wood is stiff, flat and dense, has no surface knots and is easily machined.
Machining, sawing and sanding MDF wood creates a considerable amount of fine dust that irritates the eyes, nose and lungs. MDF binding resin contains urea formaldehyde---a material that may be released when machining, drilling or cutting. The Agency for Toxic Substances and Disease Registry (ATSDR) classifies formaldehyde as a likely carcinogen (cancer causing substance) in humans. Anyone attempting to machine MDF wood should wear protective clothing, eye goggles, respirators and/or face masks. Another distinct disadvantage of MDF wood is its weight. It is an extremely heavy composite wood, and a single sheet 0.25 inches thick weighs almost 45.4kg. MDF wood tends to blunt hand tools due to its high-binding glue content. Medium density fiberboard is liable to splitting if you don't take appropriate care when nailing or screwing. It is recommended that screws be no further than 25 millimetres from the edge of the board.