| Titre : |
Changing nature of wood products - What does it mean for coatings and finish performance |
| Type de document : |
texte imprimé |
| Auteurs : |
Charles Jourdain, Auteur ; Jack Dwyer, Auteur ; Keith Kersell, Auteur ; Douglas Mall, Auteur ; Ken McClelland, Auteur ; Robert Springate, Auteur ; Sam Williams, Auteur |
| Année de publication : |
1999 |
| Article en page(s) : |
p. 61-66 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Assemblages (technologie)
Composites
Panneaux de fibres
Panneaux de particules
Revêtements:Peinture
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
As the fundamental nature of North American forest has changed over the past 200 years, so have the properties of the building products derived from those forests. Smaller diameter secondand third growth trees yield lumber with higher percentages of knots and sapwood and less of the clear fine grain lumber traditionally used for architectural applications. Many of the current recommendations for finishing exterior wood products are based upon dated information. The more knotty solid wood products used today may have coarser grain and be predominantly flat-grained. Flat-grained lumber is more prone to grain raising and dimensional change. Saw-textured surfaces decrease the potential for grain raising and they enhance finish performance. Saw-textured knotty flat-grained wood products may perform better if they are finished with penetrating finishes (semitransparent stain) rather than with film-forming finishes (paints). Semitransparent stains and other types of penetrating finishes do not peel and tend to be less likely to show knot or extractives bleed. Film-forming finishes may also be used on knotty saw-textured flat-grained surfaces, however discoloration because of bleed-through at the knots continues to be a challenge, particularly with light-colored finishes.
Use of different wood species, flat-grained knotty wood, and composites may require some changes in finishing practice and more careful selection of products for specific uses. For example, if a white painted look is desired, it may be better to use a paper-overlaid product to eliminate problems with knot bleed than to try to seal the knots using shellac. If finger-jointed lumber is used, extra care may be required to assure that the finish can adequately block the extractives. Sealing and painting the edges of composites is necessary to assure good performance. Paper-overlaid products give a good surface for painting.
Advances in finger-jointing and factory prefinishing will add to the performance of modern wood products. In the coming decade, the transition to lumber from rapidly grown intensively managed forests will continue. New species and composites will become more available in the marketplace. Much of the burden for assuring the compatibility of finishes with new wood products will probably rest with the woatings manufacturers and their suppliers. The technology of paints and other finishes and the protocols for testing finishes must advance to keep pace with the changes in the substrates. |
| Note de contenu : |
- WOOD PROPERTIES
- EXTERIOR WOOD PRODUCTS : Architectural products and species - Imported wood species - Silvicultural practices to enhance wood quality - Lumber grades and quality - Flat-grained siding and lumber-effect on finishing - Wood/wood composites - Wood/plastic composites - Paper-overlaid products - Fiberboard
- PAINTING GUIDELINES : Flat-grained solid lumber and siding - Finger-jointed lumber and siding - Plywood - Wood/wood composites - Wood/plastic composites - Paper-overlaid products - Fiberboard - Factory priming and finishing |
| En ligne : |
http://www.fpl.fs.fed.us/documnts/pdf1999/jourd99a.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18038 |
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 71, N° 890 (03/1999) . - p. 61-66
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