Fiberboards 2879 



Table 23- 1 1 . — Identification of 'A- and 'A-inch-thick hardboard panels evaluated 

 by Werren and McNatt (1975; text footnote 5)' 



Letter designation Method of Condition Designation 



of manufacturer^ felting at pressing of surfaces 



A^ Wet Wet Screenback 



B Wet Wet Screenback 



C Wet Dry S2S 



D Air Dry S2S 



E^ Wet Wet Screenback 



F Wet Wet Screenback 



G Wet Wet Screenback 



H Wet Dry S2S 



J^ Air Wet Screenback 



K Air Dry S2S 



L Air Dry S2S 



'Ten or 20 panels of each of the two thicknesses from each manufacturer were evaluated. S2S 

 means smooth on both sides. 

 H is not part of the series. 

 ^These hardboards are emphasized in data plots associated with discussion of this experiment. 



Hardboard properties. — Within each manufacturing plant properties of 

 commercial hardboards vary as processes are modified and composition of wood 

 furnish is altered. Properties of hardboards manufactured in different plants also 

 vary significantly. Werren and McNatt (1975),^ in cooperation with the Ameri- 

 can Hardboard Association and eleven hardboard manufacturers, evaluated and 

 summarized these differences. Of the 1 1 hardboards evaluated, seven were wet 

 felted (five wet pressed and two dry pressed), and four were air felted (one wet 

 pressed and three dry pressed); the wet-pressed boards had one screened surface 

 and the dry-pressed boards were S2S, i.e., smooth on both faces (table 23-1 1). 



^Werren, F., and J.D. McNatt, 1975. Basic properties and their variabiUty in 20 commercial 

 hardboards. U.S. Dep. Agric. For. Serv., For. Prod. Lab. Internal Rep., Madison, Wis. 



