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PropertiesMDF properties The properties of MDF can vary based on cost and region of the country where it is produced. It’s important to select a grade of MDF produced by a given mill that matches the functionality and coatability required by the end product for edge finish, rout quality, face-sanding degree, and screw holding power. Factors that affect these properties are listed below. The internal bond strength of the board must be greater that 130 pounds per square inch (psi). Boards that approach 150 psi perform very well. Boards that machine well have internal bond strengths that work well for powder coating. With the IR process, the internal bond strength properties are not degraded. The moisture content of the board should be within 5 percent to 7 percent for optimum coating. Lower than 5 percent requires more preheat temperature, and sharp corners may become difficult to coat. The average density of MDF should be 45 to 48 pounds per cubic feet (lb/cu ft). The density profile needs to be as flat as possible and not drop below 40 lb/cu ft at the core of the MDF. Sample A, with sharp changes in density profile, will have a greater tendency for the MDF to crack during the heating cycles than sample B that has a more constant density distribution across the board thickness. (See Figure 2.) Lower quality MDF have a large differential between the core density and the face density, causing edge cracking during the heating process. The fiber type (soft or hard wood) of the MDF has little effect on the two-coat process. The length of the fiber affects the sandability of the MDF. Shorter fibers generally provide better quality edges and are typical of MDF with higher bond strengths. | |
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MDF Powder Coat Systems, LLC | 300 Highpoint Ave., Portsmouth, RI
02871 | 401-683-7525 Email: jmartin@vulcan-mdf.com |
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