Medium density fiberboard (MDF) is made from the wood of birch and larch trees. The chippings from these trees are steamed until the materials become fine wood fibers. Resins are used to bind these fibers together, and the material is pressed into boards with the application of heat. These boards are relatively easy to paint on, but some caution must be taken when doing so. To paint MDF, you should prime the board before painting, use the proper tools to apply the paint and apply two coats of paint.
Advantages of MDF
MDF is an ideal wood to use for many interior home furnishings such as cabinetry because it is more stable and cheaper than hardwood. It also is dense and flat, and many people consider it to be attractive. It has no recognizable surface grain, so it can easily be cut, drilled, filled or machined.
Preparing to Paint
If you are planning on cutting the MDF before painting it, make sure to wear a mask or some kind of facial protection. The dust, which contains wood particles and resin, can be hazardous to your health if it is inhaled. Small holes or gaps should be filled with wood filler, and any rough edges should be sanded before you start to paint.
Priming the Board
MDF sometimes comes pre-primed, but if yours isn't, then you should prime the surface before painting. You can use any type of water-based primer, such as an emulsion paint or an acrylic primer. This base-coat of primer will help give the top coat a truer shade and will prevent it from being affected by the color of the board. The primer also will combat the MDF's tendency to result in a blotchy, uneven finish because of its porous surface.
Applying the Paint
When you are painting solid areas, paint brushes and paint rollers work well. For more intricate pieces, it's best to use spray paint instead of a brush or roller. Spray painting the MDF can cover the surfaces more evenly without resulting in an excessive buildup of paint.
More than One Coat
The best results are often obtained by applying two coats of paint and sanding the wood in between coats by using fine sandpaper. Any acrylic, water-based paint will suffice in painting a top coat of paint on the MDF. Also keep in mind that painting both sides of the board will help prevent it from bowing after the paint dries.