Composition Board Has Found Its Place in the Furniture Industry

Twelve types of composition board were evaluated in dimensional stability, hardness, and screw holding. Three major types of manufacturing processes were represented, namely, horizontal and vertical extrusion and multi-platen; the latter can be divided into many classifications depending upon the type of forming system and raw material being used. Dimensional stability was determined by veneering a 3/4 inch by 12 inch by 12 inch specimen using 1/20 inch cross and 1/28 inch face veneers. The panel was sanded, filled, sealed, scuff sanded, and given two coats lacquer. After finishing and drying, the entire panel was measured for thickness in different areas. It was then subjected to 100?F. at 90 percent relative humidity until equilibrium was reached. After examining the panel, it was then redried to the original moisture content. Panels which increased less than 0.1 percent over the original thickness were considered acceptable. Three of the panels, all multi-platen type, retained 1 percent or more and were considered not desirable. Generally as density increased, retention of swelling decreased. Hardness was determined by measuring the force required to embed a steel ball 0.44 inches in diameter to one-half its diameter (Janka test). For the 12 different types of panels tested, the range in hardness was 430 to 2,212 lbs. For the screw holding test, veneered panels were drilled with a #30 drill to a depth of 5/8 inch. The force required to withdraw a 3/4 inch #10 wood screw was determined. Face withdrawal ranged from 54 to 605 lbs. There was a good positive correlation between screw holding and density. Higher values were obtained with sheet metal screws. A study of the different types of waste material available included block waste, veneer trim, chippings, cores, and sawmill slabs. From the standing tree, excluding all bark and stumpage, 31 percent was wasted in topping. The waste in processing the log through the sawmill amounts to 27 percent. In the rough line of the furniture mill, 18 percent is wasted. With additional waste from planing and dimensioning, the total is more than 88 percent of the original tree. In the production of veneer, 22-1/2 percent is lost in the core, 6 percent in end-trim, 31 percent in green clippings, 15-1/2 percent in dry clippings, leaving only 25 percent utilized in the finished product. The fuel value of wood has been calculated to be $6.24 per ton.

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