by Gene Wengert
email@example.com WOOD DOCTOR’S Rx
QWhat is the main differ- ence between MDF and particleboard? It seems I
see a lot of variations in
weight in MDF. Is this important?
AThe difference between these two products de- pends, 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.
Next, an adhesive is added to the
fibers, and the fibers are then formed
into a very thick, loose mat, which is
pressed together with heat. The heat
cures the adhesive and makes the
fibers pliable during pressing.
The amount of fibers in the mat
and the amount of pressure determine
the product’s final density. The wood
species, as well as straightness, knotti-
ness, 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
Particleboard is manufactured by
cutting logs or small pieces of wood
See more at the Wood
Dr. Knowledge Center
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Sponsored by Northwest Hardwoods.
Differences between MDF and particleboard
Redrying lumber requires great care.
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Gene Wengert, “The Wood Doctor,” has been training
people in efficient use of wood for 35 years. He is
extension specialist emeritus at the University of Wisconsin-Madison.