Erosion Rates of Wood During Natural Weathering. Part I. Effects of Grain Angle and Surface Texture

Authors

  • R. Sam Williams
  • Mark T. Knaebe
  • Peter G. Sotos
  • William C. Feist

Keywords:

Weathering, erosion, flat grain, vertical grain, wood properties

Abstract

This is the first in a series of reports on the erosion rates of wood exposed outdoors near Madison, Wisconsin. The specimens were oriented vertically, facing south; erosion was measured annually for the first several years and biannually for the remainder of the exposure. In the work reported here, the erosion rates of earlywood and latewood were determined for smooth-planed vertical-grained lumber and abrasive-planed and saw-textured flat-grained plywood for an exposure period of 16 years. Lumber species were southern pine, western redcedar, Douglas-fir, and redwood; plywood species were western redcedar, Douglas-fir, and redwood. Erosion rates varied from 34 μm/year for southern pine latewood to 101 μm/year for western redcedar earlywood. Large differences were observed between earlywood and latewood erosion rates during the first 7 years of weathering, but not during subsequent years. A significant change in the erosion rate of just the latewood was observed for redwood, western redcedar, and Douglas-fir after approximately 7 years of exposure, and for southern pine, a significant change occurred after approximately 12 years of exposure. The erosion rates of vertical-grained lumber were higher than those of flat-grained plywood. Only slight differences were observed for saw-textured as compared to smooth plywood.

References

Arnold, M., J. Sell, and W. C. Feist. 1991. Wood weathering in fluorescent ultraviolet and xenon arc chambers. Forest Prod. J.41(2):40-44.nBentum, A. L. K., and F. W. Addo-Ashong. 1977. Weathering performance of some Ghanaian timbers. Technical Note 26, Forest Products Research Institute, Ghana.nBluck, J. M., and E. A. Mraz. 1974. Inorganic surface treatments for weather-resistant natural finishes. Res. Pap. FPL 232, USDA, Forest Serv. Forest Prod. Lab. Madison, WI. 40 pp.nBrowne, F. L. 1960. Wood siding left to weather naturally. Southern Lumberman201(2513):141-143.nDeppe, H. J. 1981. A comparison of long-term and accelerated aging tests on coated and uncoated wood-based materials. Holz-Zentralblatt107(63-64):1051-1054.nDerbyshire, H., E. R. Miller, and H. Turkulin. 1995a. Assessment of wood photodegradation by microtensile testing. Drvna Industrija46(3):123-132.nDerbyshire, H., E. R. Miller, and H. Turkulin. 1995b. Investigations into the photodegradation of wood using microtensile testing. Part 1. The application of microtensile testing to measurement of photodegradation rates. Holz Roh-Werkst.53(5):339-345.nDerbyshire, H., E. R. Miller, and H. Turkulin. 1996. Investigations into the photodegradation of wood using microtensile testing. Part 2. An investigation of the changes in tensile strength of different softwood species during natural weathering. Holz Roh- Werkst.54:1-6.nDerbyshire, H., E. R. Miller, and H. Turkulin. 1997. Investigations into the photodegradation of wood using microtensile testing. Part 3. Holz Roh- Werkst.55(5):287-291.nEvans, P. D. 1988. A note on assessing the deterioration of thin wood veneers during weathering. Wood Fiber Sci.20(4):487-492.nEvans, P. D. 1989. Structural changes in Pinus radiata during weathering. J. Inst. Wood Sci.11(5):172-181.nEvans, P. D. 1996. The influence of season and angle of exposure on the weathering of wood. Holz Roh- Werkst.54(3):200.nEvans, P. D., P. D. Thay, and K. J. Schmalzl. 1996. Degradation of wood surfaces during natural weathering. Effects on lignin and cellulose and on the adhesion of acrylic latex primers. Wood Sci. Technol.30(6):411-422.nFeist, W. C. 1990. Outdoor wood weathering and protection. Ch. 11 in R. M. Rowell and J. R. Barbour, eds. Archaeological wood: Properties, chemistry, and preservation. Advances in Chemistry Series 225. Proc. 196th meeting, American Chemical Society; 1988 September 25-28, Los Angeles. American Chemical Society, Washington DC.nFeist, W. C., and E. A. Mraz. 1978. Comparison of outdoor and accelerated weathering of unprotected softwoods. Forest Prod. J.28(3):38-43.nFeist, W. C., and D. N.-S. Hon. 1984. Chemistry and weathering and protection. Ch. 11 in R. M. Rowell, ed. The chemistry of solid wood. Advances in Chemistry Series 207. American Chemical Society, Washington, DC.nFuto, L. P. 1976. Effects of temperature on the photochemical degradation of wood. I. Experimental presentation. Holz Roh- Werkst.34(1):31-36.nOstman, B. A. L. 1983. Surface roughness of wood-based panels after aging. Forest Prod. J.33(7,8):35-42.nSell, J., and U. Leukens. 1971. Investigations on weathered wood surfaces. Part II. Weathering: phenomenon of unprotected wood species. Holz Roh- Werkst.29(1): 23-31.nSell, J., and W. C. Feist. 1986. Role of density in the erosion of wood during weathering. Forest Prod. J.36(3):57-60.nWang, S. Y. 1981. Studies on the properties of wood deterioration. VI. The reduction in strength properties of some Taiwan species after 4 years exposure in outdoor environments. Quart. J. Chinese Forestry14(4):29-39.nWang, S. Y. 1990. Reduction of mechanical properties of seventeen Taiwan native-wood species subjected to a seven-year exposure in an outdoor environment. Mokuzai Gakkaishi36(1):69-77.nWang, S. Y., C. M. Chiu, and Z. C. Chen. 1980. Studies on the properties of wood deterioration. 1. The weathering resistance of sixteen different Taiwan native wood species tested by accelerated weathering resistance method. 2. The decay resistance of eighteen different Taiwan native wood species tested by accelerated decay resistance method. Quart. J. Chinese Forestry12(1):21-39 and 13(1):55-93.nWilliams, R. S. 1987. Acid effects on accelerated wood weathering. Forest Prod. J.37(2):37-38.nWilliams, R. S., and W. C. Feist. 1985. Wood modified by inorganic salts: Mechanism and properties. I. Weathering rate, water repellency, and dimensional stability of wood modified with chromium (iii) nitrate versus chromic acid. Wood Fiber Sci.17(2):184-198.nYata, S., and T. Tamura. 1995. Histological changes of softwood surfaces during outdoor weathering. Mokuzai Gakkaishi41(11):1035-1042.nYoshidsa, H., and T. Taguchi. 1977. Bending properties of weathered plywood. Mokuzai Gakkaishi23(11):547-556.n

Downloads

Published

2007-06-05

Issue

Section

Research Contributions