Structural Flakeboards and Composites 



2981 



Table 24-15. — Internal bond strength of flake board as related to proportions of sweet- 

 gum and white oak in the board 



'Lathe flakes; board density at test, 42 pounds/cu ft. 

 -Veneer flakes; board density at test, 46 pounds/cu ft. 



Table 24-16. — Internal bond strength offlakeboard related to proportions of five low- 

 density southern hardwoods mixed with white oak^-^ 



Low-density 

 species 



Ratios of low-density hardwood to white oak 

 100/0 75/25 50/50 25/75 0/100 



PANEL DENSITY: 42 POUNDS/CU FT 



Sweetgum 169 150 



Sweetbay 267 157 



Black tupelo 242 163 



Red maple 269 110 



Ash sp 144 109 



PANEL DENSITY: 46 POUNDS/CU FT 



Sweetgum 196 162 



Sweetbay 236 129 



Black tupelo 385 150 



Red maple 315 180 



Ashsp 273 184 



^Unpublished data from files of C.-Y. Hse, Pineville, La. 

 ^Veneer flakes; 4 percent phenolic binder, applied as a liquid. 



Flake quality. — IB varies significantly among panels fabricated from flakes 

 (fig. 18-274abc) cut on major types of industrial flakers, i.e., drum, disk, 

 shaping-lathe, and ring flakers. Price and Lehmann (1978) found that for south- 

 em red oak and hickory panels at 52.6 Ib/cu ft, the ring-flake panels had highest 

 IB under all circumstances except for panels fabricated at 5-percent resin content 

 and exposed to accelerated aging (figs. 24-6 and 24-7). At the low resin content 

 after accelerated aging, the range among IB values for the four flakers was only 

 7 psi. The IB's of the disk, lathe, and drum panels were similar except for the 

 lathe-flake panel at 8-percent resin content under initial conditions, which had 

 higher IB. 



