2968 



Chapter 24 



Moisture content of mat. — The McMillin-Koch experiment^, and ancillary 

 work in connection with it, showed that flake moisture content before addition of 

 binder should be near 4 percent to maximize internal bond strength, but that 

 moisture content of mat surface layers should be considerably higher to maxi- 

 mize MOE. 



10 



INITIAL FLAKE 

 M.C.-4% 



47 



50 



53 



56 



DENSITY (POUNDS PER CUBIC FOOT) 



Figure 24-35. — Effect on modulus of elasticity of water-spraying top and bottom mat 

 surfaces just prior to hot-pressing three-layer board made of cold-cut lathe flakes 3 

 inches long and randomly oriented. Flake thickness was 0.025 inch in the core and 

 0.015 inch in the faces. Boards contained 25 percent each of sweetgum, hickory, 

 southern red oak, and white oak. Resin content was 5 percent and press time 5 

 minutes. (Drawing after Hse et al. 1975, from Hse and Koch^) 



