Medium density fiberboard (MDF) is becoming more popular in the building industry due to its ease of use and multiple uses. It is an engineered product that can be made into multiple shapes and sizes. While it is very easy to work with, there are some tips you may want to know before starting a project using MDF.
MDF is an engineered product made up of wood fibers, wax, and resin. Because it is engineered, you get a uniform product every time. It cuts great because it is typically very straight, does not have knots, and is very stable. Two things to be aware of when cutting MDF is that there will be a lot of dust and it tends to dull saw blades quicker than standard plywood. Because of this, you will want to wear a dust mask, eye protection, and have a vacuum ready as well as an extra saw blade.
Cutting MDF creates a sharp, or open, edge so it is important to sand all cut edges before finishing. This can usually be done with a fairly light-grit sandpaper, such as 150 grit.
MDF will swell and crack if saturated with water. Because of this, it is important not to use it in applications where it may get wet such as around a shower or sink in a bathroom. There are better products, such as cement board, for these applications.
Painters love to work with MDF. It is very stable, there is no grain, and it holds paint very well. To paint MDF, follow these tips. A solvent-based primer (oil, alcohol, or lacquer) should always be used. Water-based primers will cause the wood fibers to swell and create a type of grain. The cut edges are more porous, so it is a good idea to take some joint compound and spread it on the edge to seal the wood before priming. This should be a thin layer of the material that you can put on with your hand. Sand when dry.
Screws hold well in MDF, but this material can chip or crack near the edges. Because of this, it is a good idea to pre-drill all screw holes. This material can be pretty hard to drive a nail into, so screws are probably your best option.