MDF, or medium density fiberboard, is a composite wood product made from refined pine and eucalyptus dust in a proprietary blend with synthetic resins and binders to create a highly consistent sheet good. Think of MDF as particle board's more refined cousin. It is commonly used in the manufacture of furniture and other woodwork.
Appearance and Consistency
MDF comes in sheets varying from 3/8 inch to 1 inch. Most sheets are a standard 4-by-8 feet, although special order sheets are available with extra length. The colour is that of dark oatmeal. Since it is made from dust, MDF has no grain and is consistent in density throughout the entire thickness of the sheet. It is produced with saw-cut edges and a smooth sanded face on both sides. MDF is considerably heavier than plywood and more brittle, requiring additional support.
Medium density fiberboard can be worked with any standard woodworking tool. Since it is consistent in density, it provides a superior product for shaping and machining. MDF can also be sanded with standard sandpaper and easily allows creation of a smooth surface. MDF can be glued and nailed, although small headpin nails do have a tendency to pull through it. It should be reinforced with screws. Coarse thread drywall screws are the choice of most carpenters.
MDF can be painted or stained, although large sections stained will be noticeably void of grain, which has a strange appearance. It will take high gloss lacquer finishes exceptionally well, making it a good choice for store fixtures and other furniture pieces that require a fine finish. When painting with latex, allow 10 per cent more than you would for plywood, due to the absorption rate. Paint can be rolled or brushed on.
For higher quality products, or products that require stain, veneer core MDF is one solution. Both faces of each sheet are manufactured with a thin (less than 1/8 inch) layer of hardwood incorporated into the product. When working with veneer core, you must edge band, or veneer your edges. Additional caution is required when sanding, since the veneer has a tendency to "burn" through, leaving voids in the grain and dark marks on the surface which can show through stained finishes.