MDF

Medium-density fibreboard

Medium-density fibreboard (MDF) is an engineered wood product formed by breaking down hardwood or softwood residuals into wood fibers, often in a defibrator, combining it with wax and a resin binder, and forming panels by applying high temperature and pressure. MDF is more dense than plywood.

It is made up of separated fibers, (not wood veneers) but can be used as a building material similar in application to plywood. It is stronger and much more dense than normal particle board.

The name derives from the distinction in densities of fiberboard. Large-scale production of MDF began in the 1980s .

Comparison to natural woods

Droops when moisture is present.

Recent developments

A fairly recent development is flexible MDF sheets made by BendyMDF. These are sheets scored with multiple slots so that the material can easily be formed into curved shapes and then fixed.

Safety aspects of MDF

When MDF is cut, a large quantity of dust particles are released into the air. It is important that a respirator be worn and the material be cut in a controlled and ventilated environment. It is a good practice to seal the exposed edges to limit the emissions from the binders contained in this material.

Formaldehyde resins are commonly used to bind MDF together, and testing has consistently revealed that MDF products emit urea formaldehyde and other volatile organic compounds that pose health risks at sufficient concentrations, for at least several months after manufacture. Urea formaldehyde is always being slowly released from the surface of MDF. When painting it is good idea to coat the whole of the product in order to seal in the urea formaldehyde. Wax and oil finishes may be used as finishes but they are less effective at sealing in the urea formaldehyde.

Whether these chronic emissions of formaldehyde reach harmful levels in real-world environments is not yet fully determined. The primary concern is for the industries using formaldehyde. As far back as 1987 the U.S. EPA classified it as a "probable human carcinogen" and after more studies the WHO International Agency for Research on Cancer (IARC), in 1995, also classified it as a "probable human carcinogen". Further information and evaluation of all known data led the IARC to reclassify formaldehyde as a "known human carcinogen"associated with nasal sinus cancer and nasopharyngeal cancer, and possibly with leukemia in June 2004.