IMPACT OF THREE ALTERNATIVE SURFACING PROCESSES ON WEATHERING PERFORMANCE OF AN EXTERIOR WATER-BASED COATING

Authors

  • Julie Cool The University of British Columbia Forest Sciences Centre 2424 Main Mall Vancouver, BC, Canada, V6T 1Z4
  • Roger E. Hernández Université Laval Pavillon Gene-H. Kruger 2425, rue de la Terrasse Québec, QC, Canada, G1V 0A6

Keywords:

Black spruce wood, oblique cutting, face milling, helical planing, water-based coating, adhesion, weathering

Abstract

Oblique cutting, face milling, and helical planing were used to surface black spruce wood prior to the application of an exterior acrylic water-based coating. Surface characteristics were assessed using an environment scanning electron microscope and coating performance was evaluated through pull-off measurements before and after a 3-year natural weathering exposure. Microscopically, oblique-cut surfaces were smooth with plateau-like areas, had a low level of fibrillation and few open lumens. Face-milled surfaces were characterized by a high level of fibrillation and numerous open lumens that favor coating spreading and penetration. Helical-planed specimens had an intermediate level of fibrillation and number of open lumens. After coating application, oblique-cut and helical-planed surfaces presented similar overall visual quality, whereas face-milled samples had an irregular appearance that degraded their quality. As a result, the latter were subjected to erosion during weathering exposure which further degraded their overall quality as well as pull-off strength. More specifically, face-milled samples had a significant inferior pull-off strength both before and after weathering. Oblique-cut specimens yielded higher initial pull-off strength but were associated with higher adhesion loss. According to the results, helical planing reduces adhesion loss of the coating studied over a 3-year exposure to yield a superior pull-off strength after weathering. Therefore, surfaces having a certain level of fibrillation still firmly attached to the surface and open lumens are desirable to increase mechanical anchorage of coating on black spruce wood surfaces.

Author Biographies

Julie Cool, The University of British Columbia Forest Sciences Centre 2424 Main Mall Vancouver, BC, Canada, V6T 1Z4

Assistant Professor

Department of Wood Science

Faculty of Forestry

Roger E. Hernández, Université Laval Pavillon Gene-H. Kruger 2425, rue de la Terrasse Québec, QC, Canada, G1V 0A6

Professor

Centre de recherche sur les matériaux renouvelables

Département des sciences du bois et de la forêt

Faculté de Foresterie, de géographie et de géomatique

References

ASTM (2002) D 4541. Standard test method for pull-off strength of coatings using portable adhesion testers. American Society for Testing and Materials, West Conshohocken, PA.

ASTM (2005) G7-05. Standard Practice for atmospheric environmental exposure testing of non-metallic materials. American Society for Testing and Materials, West Conshohocken, PA.

Boutelje JB (1966) On the anatomical structure, moisture content, density, shrinkage, and resin content of the wood in and around knots in Swedish pine (Pinus Silvestris L.), and in Swedish spruce (Picea Abies Karst.). Svensk Papperstidning årg. 69(1): 1-10.

Cool J, Hernández RE (2011) Performance of three alternative surfacing processes on black spruce wood and their effects on water-based coating adhesion. Wood Fiber Sci, 43(3):1-14.

Damery DT, Fisette P (2001) Decision making in the purchase of siding: A survey of architects, contractors, and homeowners in the U.S. Northeast. Forest Prod J, 51(7/8):29-36.

de Moura LF, Hernández RE (2006) Evaluation of varnish coating performance for three surface methods on sugar maple wood. Forest Prod J, 56(11/12):130-136.

de Moura LF, Hernández RE (2007) Characteristics of sugar maple wood surfaces machined with the fixed-oblique knife pressure-bar cutting system. Wood Sci Technol, 41(1):17-29.

Feist WC (1983) Weathering and protection of wood. Proceedings of the 79th Annual Meeting of the American Wood-Preservers’ Association held in Kansas City, MO from April 17-20. Pages 195-205.

Feist WC, Little JK, Wennesheimer JM (1985) The moisture-excluding effectiveness of finishes on wood surfaces. USDA Forest Service, Forest Products Laboratory, Madision, WI, USA, 43 pp.

Hernández RE, Cool J (2008) Evaluation of three surfacing methods on paper birch wood in relation to water- and solvent-borne coating performance. Wood Fiber Sci 40(3):459-469.

Hernández RE, Riedl B, Talbot M, Cool J, Kuljich Rios S (2011) Amélioration de l’adhésion de peintures extérieures sur des lambris de bois d’épinette blanche. Final Report – Project UL103. Value to Wood - Natural Resources Canada. 77 Pages.

Ozaki S, Kimura S (1989) The oblique cutting of wood. V. Splits below the cutting plane and the ratio of shrinkage of the chips in a 90°-90° cutting situation. Mokuzai Gakkaishi 35(1):896-904.

Ratnasingam J, Scholz F (2006) Optimal surface roughness for high-quality finish on rubberwood (Hevea brasiliensis). Holz Roh-Werkst, 64(4):343-345.

Richter K, Feist WC, Knaebe MT (1995) The effect of surface roughness on the performance of finishes. Part 1 – Roughness characterization and stain performance. Forest Prod J, 45(7/8):91-97.

SAS (2007) SAS/STAT users’ guide, version 9.2. Statistical Analysis Software Institute Inc., Cary, NC.

Singh AP, Dawson BSW (2006) Microscopic Assessment of the effect of saw-textured Pinus radiata plywood surface on the distribution of a film-forming acrylic stain. J Coatings Technol Research, 3(3):193-201.

Singh AP, Dawson BSW, Hands KD, Ward JV, Greaves M, Turner JCP, Rickard CL (2010) The anatomy of raised grain on pinus radiata weatherboards. IAWA J, 31(1):67-76.

Stewart HA (1974) Face milling can improve for surfacing and flaking. Forest Prod J 24(2):58-59.

Williams RS (1999) Finishing of wood. Chapter 15 in Wood Handbook – Wood as an engineering material. Forest Products Laboratory. US Department of Agriculture. 37 Pages.

Williams RS, Jourdain C, Daisey GI, Springate RW (2000) Wood properties affecting finish service life. J Coating Technol, 72(902):35-42.

Woodson GE, Koch P (1970) Tool forces and chip formation in orthogonal cutting of Loblolly Pine. Forest Service Research Paper SO-52. Southern Forest Experiment Station, Forest Service, US Department of Agriculture. 29 Pages.

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Published

2016-04-26

Issue

Vol. 48 No. 1 (2016)

Section

Research Contributions

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