MDF, short for ‘medium density fibreboard’, is a cheaper alternative to wood. MDF is made of wood fibres that have been combined with resin to form a board. The main surface of MDF is smooth, but the edges, which when cut expose the fibres, can be rough.
Painting MDF is not difficult, but you do need to sand between each stage to keep the edges smooth. Using an MDF primer will help achieve a great finish, as the primer stops the MDF from absorbing the paint. Read on for a comprehensive guide on how to paint MDF
MDF contains formaldehyde, so make sure your mouth is covered with a face mask. You might want to wear a paper suit (like CSI) as well. MDF fibres can be very dangerous, so take precautions as this is not something you want to breathe in.
MDF has a very smooth surface, but it tends to have rough, porous edges. For a smooth finish, you need to sand the edges down, but first, lightly sand the surface.
A lightly sanded surface will give the MDF a ‘key’ that the paint can cling to. Then wipe away any dust with a soft cloth. I would avoid wetting the cloth as MDF sucks up water, which causes swelling.
The DIY Doctor recommends using a sanding block (you can make your own by wrapping sandpaper around a block of wood) to ensure a flat sanding surface.
The rough edges need to be filled up to smooth them out. While drywall compound is recommended, wood filler can also be used (see video below). Apply an even layer, leave to dry, then sand again. There is a lot of sanding in this project!
Use a solvent based primer that specifies it is suitable for MDF. Do not use latex as it causes the wood fibres to swell. Water-based primers have the same negative effect.
Priming the MDF with the correct primer will stop paint from being absorbed and wasted. Use a brush or a roller that fits with the size of the MDF you are painting.
Once the primer is dry, sand the MDF again. Use a light touch. You want a smooth surface, but without taking off the primer. You might need to prime and sand a second time to achieve this.
Rejoice, for you finally get to paint! Use a solvent-based paint so it doesn’t interact with the primer. Take a clean brush or roller (i.e. NOT the one you used for priming), dip it in your paint and apply to the MDF. Leave to dry.
Again, you might need a second or even a third coat. Moreover, if there are any rough patches, guess what? You guessed it, sand them down! I promise this post is not sponsored by sandpaper manufacturers.
For the last step, take a third, clean brush and apply a sealant. The sealant can be any type of wax or varnish compatible with your paint. Leave to dry and then admire your handiwork. No sanding for this step!
So now you know that the secret to painting MDF is to sand, sand, and sand again. MDF is a cheap and versatile material, and if you protect yourself from potentially harmful dust, it is an excellent choice for projects in your home.
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Blogger who spent childhood suffering through many house renovations, but at least now is old enough to design rooms to her taste