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Medium Density Fiberboard

Medium Density Fiberboard, or M.D.F.

 The material I hate to love...

 The reason for the above statement is I've always had a mental problem with using the cheaper sheet goods, like particle board.

Medium density fiberboard, or better known as M.D.F., is a remarkable product. There, I said it. And I mean it.

This man made product has been around in the U.S. since the late sixties, believe it or not. It has only been in the last fifteen years or so, that the popularity has sky rocketed. While it does has disadvantages, it's advantages far outweigh the disadvantages.

The bad news and initial concern to most clients, is the fact that it contains urea formaldehyde based resins. This is know as a probable carcinogen. The good news is that the manufacturers have responded to this concern, and have started finding alternative adhesives, or binders.

Newer versions are being produced, which uses straw as one of the main ingredients, replacing wood fiber, as is commonly used today.

Another big disadvantage to anyone working with this product, is it's extreme weight. Well the manufacturers have addressed this as well, in coming up with ultra lite M.D.F. Now here's a product I can really sink my teeth into. (my saw teeth). While it maintains many of the great properties of it's heavier counter part, it is far easier to deal with, when working alone.

M.D.F. is one of the materials that lead to designing the Ezee-Feed System, for my shop. As I , or my associates, often work alone, this feed device has made the weight factor, a non factor. At least in cutting the sheets.

Another concern with this product, is the very fine dust that is produced in machining it. This dust, left to roam the hallowed halls of your shop, will find it's way into every nook and cranny to be found. Therefore, dust collection is a must, since some of these crannies are found in your lungs. A dust mask is also a very good idea. In our shop we use a couple air filtration systems, in addition to the dust collector, which is hooked up to the machinery. Portable power tools, such as a router, or circular saw is often used when working with this substrate, and should have some sort of vacuum system hooked up to it. Both of these tools are capable of spreading the dust far and wide. If possible, you may want to cut or shape the pieces outside, if you don't have a good dust collection system.

Cutting and shaping should be done with carbide bits, as the glue content is hard on the edges. The edges, once shaped, are very smooth, and ready to prime. We do rub a spackle in the edges and sand them, for a perfectly smooth finish, prior to priming. Also a couple of light coats of primer is better, as is usually the case.

This material is very stable, regarding expansion and contraction, so it is a great choice for door panels, veneered items, bath vanities, (provided it is well sealed on all edges).

There is a water resistant version, which shares all the previous benefits, and there is also a "bendy board", which is M.D.F., covered with a birch plywood. See photo below. This is a great product for curved items. Another valuable use, (shown in photo 3), is M.D.F. being used as a template for cutting multiple parts.

The sheets typically come in 4' x 8' sheets, although 5' wide x 10' or 12' long is available as well. Thicknesses go from 1/8" up to 1". We regularly use the 1/8" for counter templates, and also to protect finished floors at jobsites. The cost for this material is so low, it's cheap insurance, and also impresses client's with the care we take in protecting their belongings.

Fastening M.D.F. can be done using normal techniques. Screws hold well, but must be pre drilled. Some people prefer to use sheet metal screws, instead of wood screws, but I don't feel that is a requirement. What is necessary though, is to stay several inches away from the ends, or they will split. If this happens, a squirt of super glue in the crack, and a clamp will fix that quite well. Nails and staples also hold pretty well, but we stick with screws. We'll shoot a few brads in to hold things together, and then follow up with screws. 

We use biscuits as needed, both to align edges, and give some extra strength to the joint. Yellow glues work quite well with M.D.F.

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