Medium density fiberboard

Harriet Woolmore <harriet.woolmore [at] cls__glasgow__gov__uk> writes

>It is my understanding that MDF (Medium Density Fibre board) is not
>used in museums in the United States of America for both
>conservation and health and safety reasons. At Glasgow Museums,  MDF
>is widely used both in the construction of and as dress panels
>inside display cases. ...

MDF is considered a poor choice for exhibit-case and packing-crate
construction largely because the binders and even the wood fibers
themselves will emit formaldehyde and formic acid long after
construction. These low-molecular weight compounds are difficult to
scavenge from the air and will tend to accumulate in a tightly
sealed enclosure. Adding a high-humidity environment with silica
gel, or by other means will further aggravate the situation. I'd
also be concerned about any important display materials left in
direct contact with MDF for very long. If used on its own in an open
space with normal ventilation, MDF is probably no worse than
commercial carpeting or many other typical building materials.

There are products sold here in the US under the trade-names of
Medex, or Medite-2. These are also medium-density fiberboards, and
they cut and tool in the same fashion, but they are manufactured
with an acrylic binder. The wood fibers themselves will still emit
trace amounts of formaldehyde and formic acid, but most will remain
entrained in the matrix of the material. The US supplier is Sierra
Pine: <URL:http://www.sierrapine.com/products/mdf.htm>

There is another product called MDO (Medium Density Overlay). This
is a plywood that uses an acrylic resin as a binder rather than the
nasty phenolic resins normally associated with plywood manufacture.
Here, the only threat is the naked surface of the wood itself (often
covered with a thin kraft paper), which can be equally nasty in a
tightly sealed enclosure. I've heard equivalent things said about
Marine plywood and other products that are used for outdoor signs
and such. All are more expensive than plain old MDF, but not too
much more expensive. Again, the problems are in applications that
involve a tightly sealed enclosure (like an exhibit case) or direct
contact with objects. Using such materials in an open room with
normal ventilation should not be a problem.

If you are still tempted to use MDF, just go to the shop where they
are cutting it and take a whiff! It's pretty repulsive stuff.

Craig Oleszewski
Hygrospec
New York City


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                  Conservation DistList Instance 17:4
                   Distributed: Monday, June 23, 2003
                        Message Id: cdl-17-4-012
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