Q. What is the main difference between MDF and particleboard? I see a lot of variations in weight it seems in MDF. Is this important?

A. The difference between these two products depends, in part, on how you will be using the product. What properties or characteristics do you want, strength, smoothness, stiffness? Here is a general description; work with your supplier to obtain the correct product for your use.

How MDF is made

MDF is made by taking wood and breaking it all the way down into the basic cell or fiber (the same as we do when making paper) or clumps of fibers. If this breakdown is done using water, then the water is extracted.

Then, an adhesive is added to the fibers and the fibers are then formed into a very thick, loose mat, which is then pressed together with heat. The heat cures the adhesive and makes the fibers pliable during pressing.

The number of fibers in the mat and the amount of pressure determine the product’s final density. The wood species, as well as straightness, knottiness, log diameter, and length are not very important overall, so this allows MDF raw material costs to be quite low.

As an aside, the story is told about a person named George, who was operating a press, pressing the fibers, prepared similarly to MDF and paper, without glue into the ubiquitous, light-weight ceiling tiles. We might refer to the tiles as Low-Density Fiberboard.

The story goes on: When George went to lunch, he forgot to open the press and take out the product, so when he came back from lunch, he had a very thin panel, very hard panel, and very dark colored panel instead of the ceiling tiles. Somehow he was able to get the company to give him a patent for this product, and that is how George Mason became famous…the inventor of Masonite or high-density fiberboard, that uses the natural glue in the wood to hold the panel together.

With MDF, the final density and the amount of added adhesive determines most of the critical properties. So, you want a board that has enough adhesive and enough density to give you the strength and surface properties you need. Inherent in MDF is low shrinkage and swelling amount when the humidity around the panels changes…movement in width and length.

However, the thickness does change substantially, especially with exposure to liquid water. The panel, after the severe pressing to the required density actually wants to spring back in thickness; water helps this happen. So, always keep MDF dry and design with MDF so that the consumer will not get the MDF wet (perhaps using a quality coating system).

Particleboard properties

Particleboard is manufactured by cutting logs or small pieces of wood into chips. The chip size can vary from large (also called flakes or wafers) to quite small. With large chips, there are likely to be some tiny voids in the board where adjacent chips bridge a gap between them.

A larger chip size usually means a lower density board; smaller chips give a smoother surface and higher density. (A three-layer board with large chips in the interior and smaller chips on the outside gives a smooth surface without an extremely high density.) Inherently, a denser wood species means a denser board.

The amount of adhesive required depends on the final properties needed and the size of the chips themselves. As might be expected, therefore, particleboard properties and characteristics are quite varied depending on the raw material species (density mainly), amount of adhesive, and chip size.

The amount of pressure used is also an important factor. Chips are often long and skinny in width. The orientation of the chip affects the board’s strength and stability. As with MDF, exposure to water can create excessive swelling.

MDF vs. Particleboard

We can compare an MDF panel with particleboard and get results that favor one or the other depending on the board’s specifications. Higher density and more adhesive typically mean a strong, stiffer board.

Both products require special fastening systems. Sometimes MDF can be used as an exposed surface (rather than laminating another material on the exposed face) with printed grain and embossing to give a look similar to solid wood.

Note: In my dealings with many companies that use particleboard or MDF and that have manufacturing issues, I find that oftentimes imported panel products (i.e., those not made in North America) may have good written specifications but are lacking in average quality and also have a wide variation in quality from piece to piece and load to load. Some imported products also seem to have formaldehyde issues from time to time.