2834 



Chapter 23 



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 I 

 I 



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BOARD THICKNESS 



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Figure 23-64. — Density profile of S2S dry-formed hordboard. (Drawing after 

 1977.) 



Spalt 



measurement and moisture content control. Such a system developed by the 

 Measurex Corporation has been applied to the dry-process hardboard siding 

 plant in Paris, Tenn., operated by the Celotex Corporation. Readers needing an 

 illustrated description of this system are referred to Betzner and Wallace (1980) 

 or to Suchsland and Woodson (1985). 



MEDIUM-DENSITY FIBERBOARD 



Medium-density fiberboard (MDF), according to common usage of the 

 term, refers to thick (Vh- to 1-inch plus) fiberboard sold in the industrial core 

 stock market in direct competition with particleboard. The manufacturing proc- 

 ess is therefore controlled to produce a product with bending strength, modulus 

 of elasticity, internal bond, machinability, and screw-holding power sufficient 

 for these applications. These requirements have not been determined precisely; 

 the commercial standard simply identifies those materials that are being success- 

 fully used in these applications in terms of certain properties which can readily 

 be evaluated by the manufacturer, and which can be maintained within certain 

 tolerances. 



The medium-density fiberboard process has been developed for uses which 

 are different from all other fiberboard applications. Experience and research 



