Medium density fiberboard or MDF can be a versatile and useful building or finishing material. It offers incomparable evenness and consistency of thickness and texture ideal for some projects. It is a type of engineered wood made of finely separated wood fibers bonded with resin and wax.
MDF has no grain or separate layers such as plywood. Because of the high resin content, it is a dense material with a hard surface. This density is great for durability, fastening, and stability – but it does cause concern when it comes to shaping or planing.
So, we’ll look at some guidelines and suggestions to help.
Can You Run MDF Through a Thickness Planer?
There are probably not many circumstances that require you to run MDF through a thickness planer, because it is typically uniform in thickness and texture.
One reason you may consider using a thickness planer for MDF is to level and smooth out the area where two pieces of MDF are joined. This may be done more efficiently with a hand planer, but we’ll get to that in a bit.
Another reason could be that you need to reduce the thickness of a piece for a custom fit. If this is the case hopefully, it will be minimal. Heavy use of a planer on dense material like MDF can cause rapid wearing of the tool’s blades. We’ll explain more about that below.
Can You Plane MDF Using a Manual Hand Planer?
Using a manual hand planer may be one of the best choices if you are smoothing or leveling a joint. Though inconsistencies between sheets of MDF are not too common, there may be times when a joint has either slight swelling or a lip at the joining point.
Once glued and dried well enough to work with, you can gradually run the manual hand planer over the joint to level it out before sanding it. It is a safe alternative to other methods that have more potential to damage the material.
Can You Plane MDF Using a Power Hand Planer?
It’s worth keeping in mind that a power hand planer is a tool more suitable for planing the edge or side of an MDF piece rather than the broad surface.
What Is the Best Type of Planer for MDF?
The best planer for MDF depends on the amount of material you need to remove, and the size of the material you need to plane.
To shape or reduce the edging or sides of MDF, a power hand planer would be the most efficient tool.
If you need to plane a joint between two sections of MDF a thickness planer can be used. The hardness of the resin in MDF can cause rapid wearing of the blades, so you might want to use a thickness planer for MDF only when necessary.
If you have minor adjustments to make over an MDF joint, a manual hand planer works well. It also allows for more control and less chance of damage to the surface. Finish sanding can be done afterward to smooth any lines or grooves left by the planer.
How to Plane MDF
The first thing to consider if you are going to plane MDF, is your safety. MDF contains a large amount of resin. Cutting, sanding, or planing MDF can release a large quantity of formaldehyde into the air. You’ll want to wear a good quality respiratory mask and safety goggles.
You should also consider wearing protective clothing such as long sleeves and gloves to limit skin exposure to MDF dust. It is also a good idea to use a dust collector if possible.
If you are using a manual hand planer or a power hand planer, make sure your material is securely clamped and your blade angle shallow enough not to damage the surface. For manual planing, run it over your joined area swiftly at a slight angle and take it gradually so as not to dig into the material too much.
Because of MDF’s flexibility, make sure it is supported well if you are running it through a thickness planer – especially if you have any joined areas. This can avoid having your material break at the joined seams.
3 Reasons Not to Plane MDF
While you certainly can plane MDF, there are some reasons not to:
- Rapid wearing and dulling of the planer blades: As previously mentioned, MDF contains fine wood fibers bonded with a lot of resin. The hardness of the resin creates a lot of resistance for planer blades to work through. This can result in dull blades in a very short time.
- Potential damage to a finished surface: If the surface of your MDF is the finished product, you could possibly risk damaging the uniformity of that surface by planing it.
- Harmful dust: If you are not able to take safety precautions to protect yourself or others from MDF dust, you may want to avoid planing it. This is especially the case with power planers.
2 Alternative Ways to Reduce Your MDF’s Thickness
If you don’t have a planer or the drawbacks of planing an MDF are enough to keep you from doing it, here are two other ways to make your board thinner:
- A belt-sander can reduce the thickness of MDF safely, especially if it is over a reasonably small portion such as a joint. Sanding MDF however, will roughen the surface, making it much more porous and possibly more susceptible to moisture damage. Priming and sealing the MDF after power sanding is always a good idea.
- An orbital sander can work for minor surface and depth adjustments. You may want to use coarse-grit sandpaper to break the hard surface of MDF. You will want it to be aggressive enough to break into the surface and level out uneven points. You can use fine sandpaper afterward to smooth out any rough textures.
While planing MDF is not typically recommended for the well-being of your planer blades there may be times when it is necessary. Hopefully, reading these tips and recommendations has been helpful.
Always remember the safety precautions of operating power tools and working with chemical components such as glues and resins such as those found in MDF and other similar materials.