Veneer shorts

Fine residues of the woodworking iiufustiy such as sawdust, shavings and veneer shorts are in low demand and are used as a fuel at best. The amount of these residues is quite impressive. For example, veneer shorts comprise 15 to 20% of the amount of veneer blocks while the amount of sawdust is up to 12% of the volume of sawlogs. Nowadays the carbonisation of these wood residues is an industrial practice. However, the charcoal yield is only IS to 20% on the o.d wood basis if modem industrial carbonisation units such as a Heneshoff furnace (roaster) is used (2). One of the main... 

Diisocyanates have also generated interest as adhesives for plywood, but they have mainly failed in use because of economics and adhesive application problems (adhesive distribution, penetration into veneer, etc.). Further experiments have shown that mixtures of diisocyanates with the usual fillers and extenders have a very short potlife or give nonhomogeneous glues (5,6). 

The round-up lathe. There are advantages in partially rounding up the log prior to passing it to the main lathe. In the round-up lathe the eccentricity, sweep and taper of the log are largely removed until recovery of short lengths or widths of veneer appears viable, at whieh point the bolt is prepared and ready for the main lathe. The round-up lathe reduees significantly the amount of unproductive time at the main lathe. Furthermore, any dirt or stones clinging to the log mark the round-up knife rather than the main veneer knife which must be kept in perfect condition if it is to cut quality veneer. 

Short press times under the same conditions of pressure and temperatme as in (1) yield poor welding, or no welding at aU, in the veneers interphases. 

The range of wood-based boards, and the applications in which they are used, is large, and increasing. Examples are the use of plywood in structural situations, such as I-beams or box beams, on the one hand, to the construction of short-Uved products, such as coffins from veneered particle board. Not all types of wood-based boards are suitable for aU uses. 

There is no short cut to achievement. Life requires thorough preparation—veneer isn t worth anything. 

A three-layer board having a corncob core and wood veneer face was produced for a short time in Czechoslovakia after World War II [9]. Corn stalks, like many agricultural fibre sources, consist of a pithy core with an outer layer of long fibres. Corn stalks and cobs are either hammer milled into particles or reduced to fibres in a pressurised refiner. 

Oriented Strandboard (OSB). Oriented strandboard (OSB) panels have been developed as an alternative to plywood in building construction. The emergence of OSB was driven in part by a decreased supply of large diameter logs suitable for veneer production, and by innovation and productivity changes in the North American wood products industry over the past few decades as well as the structural performance of OSB products, which are suitable for use in most plywood applications but at a much lower cost. In addition, OSB manufacture allows small, low grade timber resources to be processed into a marketable product. This effectively saves raw materials that are in short supply and promotes efficient utilization of wood (3,5,6). 

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