A form of Medium density fiberboard (MDF) that is lighter-weight and softer, likely due to less resin. MDF is manufactured from a mixture of fine wood fibers and resin bonded together then compressed into sheets with smooth, flat surfaces.
Synonyms and Related Terms
Commercial products: Medex; Medite; Medite II; Masisa; Fibrex;
- Exhibit: case construction. Product is usually used for surface/exterior construction due to its smooth surface texture. Not normally used as main structural support and not normally used in case interiors or close to objects without other sealing methods applied. Sometimes used as a case deck interior.
Dust and chemicals released when worked. Dust control system is important. Particulate mask/respirator, eye protection. Potential for sensitizing with prolonged use.
- Masisa ultralight (urea formaldehyde resin): MSDS
- Trupan MDF; Fibrex (amino resins): SDS
- Medite MDF (listed as no added formaldehyde): SDS
Although lower formaldehyde content than standard MDF, it is not really safe to be inside cases. Any wood product may release VOCs (volatile organic compounds). Specifically, wood products release aldehydes, terpenes, and acids . The types and quantities of VOCs released depends on wood species, as well as the presence of coatings . Generally, the most VOCs are released when the product is new. Barrier layers (i.e. coatings) can be applied to limit the release of VOCs.
Physical and Chemical Properties
MDF is more dense, and thus heavier per square foot than plywood or lumber. Due to its construction of wood particles and resin, the product is not as strong as traditional plywood or lumber; it is very easy to dent. It should not be used for packing. Drilling the soft, weak material is problematic and may cause dimpling of surface around penetration entry; pre-drilling and countersinking is advised.
There is a noticeable distinction between cut edge and other edges. Edges must be sealed to create an equally smooth surface, as unsealed areas absorb applied materials into a porous interior core. Some suggested methods for sealing machined areas are: use of alcohol based primer, use of two part body filler agent, use of glazing agent, use of multiple primer coats with sanding in between coats, two part resin coating, and a wood glue and water doping application. The specific method should be chosen based on final application and use of material. All methods should be independently tested if using around objects.
Note when purchasing that many distributors will substitute similar brands and materials when ordering. If you are very specific about which product you order, it can get expensive and wait times can be long.
Forms and Sizes
- Standard: 4’ x 8’ panels
- Oversize: Some products are available up to 6’ wide and 12’ long.
- Fire retardant based MDF is only available up to 5’ x 10'
- Thicknesses from 1/4” up to 1” depending on manufacturer
Resources and Citations
- Exhibit Guidelines Technical Notes: Using Composite Panels in Exhibit Case Construction