The purpose of this study was to determine flatwise and edgewise bending strength ("MOR") and stiffness ("MOE") of spruce and pine 1.5-inch by 3.5-inch by 48-inch laminated veneer lumber ("LVL") specimens parallel to grain. The experimental spruce and pine data was pooled together to give a combined spruce-pine data set.
Appendix 1 to Forestry Canada No. 35, Contract no. 1812L007 on
lumber and laminated veneer strength.
The purpose of this small study was to examine the effect of various test methods upon the bending moduli of elasticity and to determine the bending strength of selected Douglas-fir and spruce laminated veneer lumber specimens.
There is a need to develop wood preservatives based on low toxicity, low environmental impact chemicals, particularly for the residential market as the general public becomes more aware of the chemicals currently in use. Although the health hazards of treated wood may be negligible, the public perception of potential hazards may be sufficient to proscribe the future use of the present chemicals. Opportunities also exist in overseas markets for boron treated lumber provided that a rapid and cost effective diffusion process can be developed. The proposed approach to this problem, and progress made in 1991/92 are discussed.
Tests of the TotalStat electrostatic spray system were done. Two TotalStat linear nozzles were set up to apply oil-based chemical solutions from both above and below onto lumber being propelled through a spray booth. Experimental solutions of three antisapstain chemicals known to be effective in aqueous formulations were formulated in either, or both, light mineral oil (paraffin oil) and Canola oil (rapeseed oil). After periods of two and four months the treatments were rated against aqueous formulations applied by conventional hydraulic treatment. The potenial of low-volume, linear, electrostatic spray nozzles and oil-based fungicidal chemicals was evident. Further refinement of the system and formulation improvements are suggested.
The refractory heartwood of species such as spruce and lodgepole pine can now be treated to meet Canadian wood preservation standards. This is a consequence of a series of innovations in incising technology originating in the Pacific Coast region of North America. Double-density incising, developed by Forintek, coupled with the Gen II PermacisorR developed by B.C. Clean Wood Preservers Ltd. provides a sufficient density of incisions for spruce-pine-fir lumber to be effectively treated without destroying its surface appearance. However, drying to around 30% moisture content and pressure treating for longer than is commonly done at present will be required to meet the standards.
Stake testing confirms, under natural biological and weathering conditions, the results of laboratory experiments on preservative efficacy. It is required by international authorities for approval of new preservatives. Forintek is the principal source in Canada for the development of performance data on preservatives currently approved for use, and on alternative preservatives which have been identified as potentially useful for the Canadian wood treating industry. Three sites are maintained for this purpose, containing several thousand treated stakes. These are located at Petawawa National Forestry Institute near Chalk River, Ontario; at Forintek's Eastern Laboratory in Ottawa; and at Westham Island, near Vancouver, B.C. This report summarizes preservative performance at Westham Island.
A series of dispersion-resin plywood formulations were prepared in the laboratory and their bond performance assessed on incised spruce veneer at 10% m.c. Excellent bond quality results were achieved in these laboratory experiments as indicated by high average % wood failure values of over 90%. To further develop the plywood dispersion resin, a pilot plant trial at a gluing company was conducted and again excellent bond quality results were achieved. A large quantity of the plywood dispersion resin was prepared and a successful mill trial at Cantree Plywood was carried out. This trial demonstrated that more dimensionally stable panels can be prepared from high m.c. veneer. The waferboard dispersion technology developed in this study helped facilitate a mill trial using high moisture content face wafers.
The recent introduction of optimizing technology for cross-cutting boards (chop saw operation) has raised questions about the merits of this technology versus conventional manual systems in the British Columbia remanufacturing sector. A review of the existing technology available to chop lumber (both manual and computerized) was undertaken. A total of 30 remanufacturing plants were visited. Background material was obtained from journal articles and literature from suppliers. The relative merits of the systems in use are discussed.
Western hemlock is a species that is highly susceptible to compression wood (CW) formation, an abnormal wood tissue that forms on the under side of leaning tree stems and branches. When lumber cut from logs containing CW is dried, the CW shrinks approximately 10 times normal in the parallel to grain direction, resulting in degrade, at times severe, due to warp in the form of crook and bow. In this project a technique using an ultrasonic materials evaluation system (UME) was tested for its ability to detect CW. Since stress wave velocity, in addition to being dependent on elastic properties and material density, is also a function of growth ring orientation, a slope of grain indicator was evaluated for its ability to measure growth ring orientation, to be used in conjuction with the UME.
