Small-size pines suitability for glueboards

The aim of the research was to evaluate the suitability of small-size pine as a raw material for glueboard. A further aim was to investigate claims that dead knots and the twisting of the heartwood cause, quality problems in the but of the small-size pine. The theoretical framework of the study details the whole manufacturing process from raw material to the finished article; the description of the qualities of raw material, the sawing and drying processes as well as the making of the glueboard. The solve the research problem the following figures were calculated: amount of small-size pines, the yield and quality of sawn timber which can be used for making glueboard as well as the variables which affect the various stages of the process. The results show that about half of the timber from the thinning process was suitable material for sawing. The most common problem with the unsuitable timber was form defects of the stem. The average usage ratio of sawing was 2,31 k-m3/m3. 87,97 % of the sawn timber could be used for the production of glueboard. The unsuitability of sawn timber for making glueboard was mainly caused by breakage and the twisting of the heartwood. Dead knots were small and did not effect the quality of the but of the small-size pine. It can therefore be concluded that small-size pine is suitable raw material for glueboard.