Answers to Everyday Questions : How do I paint MDF correctly ?

Medium density fiberboard or MDF is quite easy to paint on, but you have to be extremely careful when doing so. MDF is made from the wood of larch and birch trees. Steaming the chippings of these trees make the material become fine wood fibers. Resins are used to bond these fibers together; the material is then pressed into boards with heat application to flatten and produce MDF.

MDF is a perfect wood to use for most interior home furnishings like cabinetry because it is more stable, cheaper and attractive than common hardwood. It is also flat and dense, and because it has no identifiable surface grain, it can easily be cut, filled, drilled, or machined. If you are planning to cut a medium-density fiber prior to painting it, make sure you always wear a mask or some kind of facial protection because the dust that contains resins and wood particles can be dangerous to your health should you inhale it. Small gaps or holes should be filled with wood filler and rough edges should be sanded before you begin painting.

MDF sometimes comes painted with primer, but if yours is not, then it is vital to apply prime paint to the surface before painting. You can use any type of water-based primers such as emulsion paint or a proprietary acrylic primer. This base-coat of primer will help give the top coat a more natural shade and will keep it from being affected by the color of the MDF. The primer will also keep MDF’s tendency to result in an uneven, blotchy finish because of its porous surface. Paint rollers and brushes work well if you are painting solid areas.

If you are painting intricate pieces, it is best to use spray paint instead of a roller or brush. This way, you can cover the surfaces without too much build-up of paint. Best results are often achieved by applying two coats of paint and sanding the wood with a fine grit in between coats. Any water-based, acrylic paint will be enough in painting a top coat of paint on the MDF. Also, remember that painting both sides of the MDF will help avoid bowing when the paint dries.