Medium density fiberboard, or MDF, is a composite wood product similar to particleboard. It's made out of wood waste fibers glued together with resin, heat, and pressure. MDF is appropriate for many applications, from cabinetry to moulding, because it is smooth, uniform, easily worked, and won't warp.

MDF has many advantages over plank wood, particleboard, or high density fiberboard. It's very smooth because the wood fibers used in its manufacture are uniform and fine. This makes it have low tear out. It has no internal voids or holes, wich make it a good choice for being routered.

MDF is manufactured using urea-formaldehyde resin which maybe released in low concentrations over a long period of time. Formaldehyde can cause temporary eye and respiratory irritation, it can also aggravate respiratory conditions or allergies in some people. Proper ventilation and precautions during working and use will reduce the risk of such problems. Some people have been reported as being affected by just a piece of MDF in a room.

This means that a coat of primer and a couple of coats of paint take well, leaving an attractive, finished surface unlike other composite wood products. MDF also has a mild reaction to moisture, meaning it won't warp or swell in high-humidity applications like a bathroom cabinet.

Builders use MDF in many capacities, such as in furniture, shelving, laminate flooring, decorative moulding, and doors. They value MDF for its insular qualities in sound and heat. Also, it can be nailed, glued, screwed, stapled, or attached with dowels, making it as versatile as plank wood. Usually, people working with MDF use a carbide saw fitted with a vacuum to reduce the amount of airborne dust. Since MDF is strengthened with resin containing formaldehyde, those at exposure try to reduce their risk of inhalation, or use special MDF with lower formaldehyde levels.

Reconstituted, engineered wood products like MDF are often covered in a veneer or laminate. These thin layers of vinyl or real wood disguise the MDF, especially along visible edges. Some people prefer using MDF over regular lumber because it has a lower impact on the environment. MDF is solely made from waste products, the leftover scraps that would otherwise be dumped in a landfill. This attraction has helped it gain popularity among homeowners. It's now available not just to contractors. Many home improvement centers and lumberyards stock it in sheets for the general public.

Working with MDF

Dust is a major hazard when working with MDF. The large amounts of dust generated by cutting and machining requires the use of proper breathing and eye protection. As a minimum, always use a dust mask while there is dust in the air, not just while actually cutting. A professional style respirator is preferable. Goggles should always be worn while using tools on MDF.

MDF can be cut in the same manner as a fine-grained hardwood although as it does not have a grain, it can be successfully sawn in any direction. MDF can also be machined, drilled and tapped.

Due to its high glue content, steel cutting tools will dull very quickly; the use of carbide tools is preferred.

Being without a grain, cutting or machining MDF will result in a very smooth edge providing that the tools are sharp and used correctly.

Fixing

Screws and nails can be used to fix MDF, however with these fixings, there is a risk of the MDF splitting if care is not taken. The risk of splitting depends upon the thickness of material, generally fixings should not be less than 25mm from the edge.

When using nails, drive them in at right angle to the surface, this will avoid bending and reduce the chances of splitting. Use ring-shank nails to ensure a good grip.

With screws, always use pilot holes - about 85 % to 90 % of the root diameter of the screw being used and at least as deep as the screw. Straight sheet metal screws with constant size shank give best results, avoid using tapered wood screws.

Because MDF can be milled to just about any profile, many of the traditional woodworking joints can be used as can dowels.

MDF can be glued using gap-filling or PVA glues. Epoxy and hot melt glues are also suitable. The edges of pieces of MDF can be glued to make larger sheets.

Finishes

As mentioned previously, MDF is typically made using urea-formaldehyde resin which will be gradually released into the atmosphere wherever MDF is used. While this will not affect most people, some people are sensitive to formaldehyde emissions so precautions must be taken. Where possible, use low formaldehyde or formaldehyde-free MDF, or consider methods of controlling these emissions through proper finishing.

Where a finish is applied, it should be applied to ALL exposed surfaces, even those not immediately visible. Finishes that work best at controlling formaldehyde emissions are solid surfaces such as laminates, vinyl covering, and finished wood veneers. Oil based paints and varnishes can be used. Less effective at controlling emissions are simple wax and oil coatings.

Home | Resources | News | Magazines | Contests

Articles | Shows | About | Contact | Site Map