The Best Paint for MDF – a Full Guide

MDF – Medium Density Fibreboard – is a commonly used building material, and is a great substitute for natural wood in many interior situations.  Its huge popularity has grown on the back of its affordable price and its frequent appearance on DIY programmes on TV.

While it may be easy to cut to shape and fix together, painting it provides slightly more of a challenge; the “faces” of the boards are very smooth, and usually take a primer quite well, but the cut edges? All sorts of problems, from a “fluffy” texture which refuses to smooth out, to paint being absorbed so much that it almost disappears, to brown stains leaching through.

The good news is that these problems can be overcome with a little thought, the right materials and the correct painting method.  In this blog I’m going to share my thoughts and experiences as a professional decorator on what the best paints for painting MDF are.  Feel free to skip ahead to the product recommendations towards the bottom of the blog if you don’t need any other information.

II’d recommend that you read this blog in conjunction with its sister article “How to Paint MDF – A Full Guide”.  The information in the two should help you to paint MDF shelves, cupboard doors and panelling confidently and professionally.

Understanding MDF

I’m a big believer in the saying “know you enemy”; if you understand the problem better, you’re better placed to figure out how to solve it.

MDF is made from the scraps of the wood industry – small unusable offcuts, wood shavings and sawdust.  I don’t know for sure, but possibly some of what goes into the “wood recycling” area at your local tip ends up in MDF too. It all gets chopped up into tiny woodchips and then steam-treated to soften it.  This softened wood “mass” is then broken down into individual wood fibres, which are then mixed with resin (to hold it all together) and wax (to give it some moisture resistance).  This mixture is then rolled out and pressed under high heat and pressure to form the sheets you see in B&Q.  I think of it a bit like taking all the scraps of meat from the butchers and mincing them together to form a burger!

Although it’s largely made of wood (around 80% wood, typically), it doesn’t behave like natural wood, and that’s where the problems can arise.

Preparing MDF for Painting

From a painting perspective, the manufacturing process described above creates beautifully smooth “faces”, but the cut edges of the boards consist of the frayed ends of thousands of wood fibres, which absorb paint and swell up, creating a rough or “fluffy” surface.  The solution is simple; the whole thing needs sanding and priming, and I cover the best way to approach this in the companion blog “How to Paint MDF – A Full Guide”.

Applying the primer both seals the surface, making it less absorbent (meaning you will get a less patchy, more even finish), and also helps your next coats of paint to adhere better to the surface.  A primer with stain-blocking properties also helps prevent those brown stains from leaching through.

Best Primers/Sealers for MDF

Recently the question was asked on Decorators Forum UK Facebook Page.  Forty-five people replied, with over twenty different answers! Which either means that there isn’t a universally accepted solution, or that lots of things work!  I found an off cut of 25mm MDF in the garage and tried nine different primers to see what would work best.  In each case I followed the same process:

• Apply first coat of primer
• Sand
• Apply second coat of primer
• Sand
• Apply first topcoat
• Sand
• Apply second top coat

I made copious notes after each stage, but the bottom line is that using any primer is better than using no primer; even a standard acrylic wood primer will do the job.  It’s not a full scientific piece of research, just one old bloke painting one piece of MDF in his garage, so don’t read too much into it, but for what it’s worth…

Based on the smoothest finish, the top three products were:

• Zinsser Cover Stain
• Zinsser Bullseye 1-2-3
• Johnstone’s MDF Primer

Based on the best opacity/stain-blocking (no brown stains showing), the top performers were Johnstone’s MDF Primer, Bedec All Prime, Dulux Uni-Primer and Zinsser Cover Stain (all very similar results).

To be completely honest though, once all the samples had had two topcoats, the differences were minimal.  My take on it would be that if you have a lot of MDF to paint, it’s worth buying a tin of the Johnstone’s MDF primer – it’s not expensive either (click here to see online prices), but if you only have a small project then use something that you can also use elsewhere, such as Zinsser Cover Stain, Dulux Uni-Primer or Bedec All Prime..

Best Topcoat Paint for MDF

So, we’ve covered the different primers you can use for this type of work. Johnstone’s Trade MDF Primer is genuinely the best option, but there are others you could go for.

As far as the topcoats go, there are a few options, depending on what you’re painting. I’ll take you through them now. I tend to stick with water-based (as do over 75% of other decorators in the UK), but I’ll give you an oil-based option too. 

Summary

Just my opinion, but if you have a large area of MDF to paint (e.g. panelling or a media wall), you may as well buy an MDF-specific primer for the job, like Johnstone’s Trade MDF Primer.

For small areas, use something that you will be able to use on other jobs, like Zinsser Cover Stain, Dulux Uni Primer or Bedec All Prime.  If you repeat the sand-prime-sand-prime process until the edges are lovely and smooth, as described in “How to Paint MDF – A Full Guide”, you should end up with a great result.

When it comes to topcoats, for smaller areas Johnstone’s Trade Aqua Guard will look great, but if you are colour drenching, or painting panelling or a media wall and want it to match the surrounding walls, then painting the whole lot with a specialist durable emulsion like Little Greene Intelligent Eggshell will give far better results.