Shelling of Growth Rings at Softwood Surfaces Exposed to Natural Weathering

Coatings

PhilipD. Evans¹  LukieH. Leung¹ 

[1] Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;

关键词: shelling;    western larch;    confocal profilometry;    profiling;    growth rings;    latewood;   

DOI  :  10.3390/coatings10090862

来源: DOAJ

【 摘 要 】

Shelling is the delamination of growth rings and the projection of woody tissue from wood surfaces. Shelling disrupts coatings and makes refinishing difficult, and a better understanding of the phenomenon is needed to help alleviate its unwanted effects. We tested whether confocal profilometry could quantify shelling in flat-faced and profiled-faced western larch deckboards exposed to natural weathering and examined the effects of growth-ring orientation and angle on shelling. Confocal profilometry was able to quantify shelling in both deckboard types. Shelling developed at the surface of flat-faced deckboards oriented pith-side-up, whereas it was absent from boards oriented bark-side-up. We found an inverse correlation between the height of shelled growth rings and the angle of growth rings to the surface of flat-faced boards. Shelling occurred in profiled-faced boards oriented pith-side-up due to the delamination of growth ring tips and projection of latewood from wood surfaces. A superficially similar although less pronounced phenomenon was seen in profiled-faced boards oriented bark-side-up. The shelling of profiled-faced boards oriented pith-side-up created lanceolate-shaped slivers of latewood that projected from the peaks of profiles. Some of these latewood tips were sharp and, for this reason, we suggest that profiled-faced western larch deckboards should always be oriented bark-side-up rather than pith-side-up.

【 授权许可】

Unknown