Medium-density fibreboard, commonly called MDF, is a versatile material used in many types of construction. MDF is used in cabinets, shelves, speaker boxes, decorative moulding, architectural modelling and many other applications. Light, durable and inexpensive, MDF is a useful material. To get the best out of it, however, it is necessary to cut it with the proper tools.
Problems with cutting MDF
MDF presents a challenge for woodworkers because of its construction. As its name suggests, MDF consists of a board made of wood fibres. These fibres are mixed with a resin binding agent and pressed into sheets at high temperatures. The variety of types of wood fibre and the high percentage of glue in the board -- around 9% of the mass of the board is resin -- mean that cutting through MDF will dull saw blades very quickly.
Saw blade material
The abrasion caused by the fibres in an MDF board can wear down a saw blade quickly. In order to prolong the edge of the blade as long as possible, the cut should be made with as hard a blade as possible. Experienced woodworkers recommend cutting this material using a saw with a tungsten carbide blade. This stiff, durable material is commonly simply called "carbide" by tool manufacturers. These tools will retain their edge longer when cutting MDF.
Type of saw blade
Most MDF cutting is done with a table saw. DIYers who purchase their MDF from a hardware store will usually be able to ask the shop to cut the board to size for them. A typical shop table saw will be a 25 cm (10 inch) blade with 50 teeth, although a larger number of finer teeth may be used for a final cut. Woodworkers working without a table saw may use a handsaw, although the process will be time-consuming.
Because of its construction, MDF tends to produce large quantities of very fine dust when cut. The person cutting the board should wear a dust mask at all times. In addition to the respiratory hazard posed by the dust itself, the binding agent in MDF contains formaldehyde. Prolonged exposure can be harmful to humans, and some people are highly sensitive to this chemical. The cut edges should also be sealed once the cut is completed.