scholarly journals Effects of Climate on Exterior Wood Coating Performance: A Comparison of Three Industrial Coatings in a Warm-Summer Mediterranean and a Semi-Arid Climate in Oregon, USA

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Kent Davis ◽  
Scott Leavengood ◽  
Jeffrey J. Morrell
Keyword(s):  
Wood Species ◽  
Fungal Growth ◽  
Natural Weathering ◽  
Specific Information ◽  
Timber Species ◽  
Coating Performance ◽  
Wood Coatings ◽  
Film Forming ◽  
Mass Timber ◽  
Wood Surfaces

Wood exposed in exterior applications degrades and changes color due to weathering and fungal growth. Wood coatings can reduce the effects of weathering by reducing the damaging effects of ultraviolet light, reducing water absorption, and slowing fungal growth on the surface. Coating performance depends on the blend of resins, oils, and pigments and varies considerably among different wood species and conditions. Specific information describing expected service for different wood species and exposure conditions is not commonly available; certain combinations may work well in one climate or on one timber species, but underperform elsewhere. This study compared the performance of three industrial wood coatings on two wood species for two temperate climates under natural weathering conditions. Most of the coatings/species combinations lost their protective properties within 12 to 15 months; however, fungal growth was more prevalent at the wetter site than at the drier site for several combinations. Film-forming coatings often peeled and cracked, while penetrating coatings weathered and changed color relatively uniformly during the study. While no coating was completely effective, the results illustrate the benefits of using coatings that promote the development of natural, uniform-patinaed wood surfaces. The findings also guide coating maintenance programs for mass timber structures exposed to natural weathering conditions.

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

scholarly journals The impact of the top coating on the mechanical properties of lacquered wood surfaces

2012 ◽  
pp. 87-100
Author(s):  
Milan Jaic ◽  
Tanja Palija
Keyword(s):  
Mechanical Properties ◽  
Wood Species ◽  
Abrasion Resistance ◽  
Direct Contact ◽  
Quercus Robur ◽  
Scratch Resistance ◽  
Indentation Hardness ◽  
Polyurethane Coating ◽  
The Impact ◽  
Wood Surfaces

This paper investigates the impact of the top coating on the basic mechanical properties of a lacquered surface, including indentation hardness, scratch resistance and abrasion resistance. Three types of the top coating were used, including a 2K polyurethane coating, a 2K acrylate-isocyanate coating and a 2K alkyd-urethane coating. Samples of two wood species, spruce (Picea abies Karst.) and oak (Quercus robur L.), were used in this study, in order to determine whether the wood species, which is not in direct contact with the top coating, has an impact on the mechanical properties of a lacquered surface. The samples coated with a 2K acrylate-isocyanate coating showed the highest values of indentation hardness, in the samples of both wood species (1.34 N for spruce; 1.4 N for oak). The samples coated with a 2K alkyd-urethane coating showed the highest values of scratch resistance (20 N for both wood species) and abrasion resistance (mass loss of 480 mg after 700 cycles for both wood species). The results have shown that the wood species does not affect the value of indentation hardness, scratch resistance and abrasion resistance of a lacquered surface.

ECONOMIC ANALYSIS OF DIFFERENT WOOD SPECIES IN MAJOR SAWMILLS IN ABEOKUTA OGUN STATE NIGERIA

2017 ◽  
Vol 17 (1) ◽  
pp. 73-82
Author(s):  
M. O ADEDOKUN ◽  
A. T OLAWUMI ◽  
J. A. SOAGA ◽  
S. A. OLUWALANA ◽  
I M. R. MOLOGMHE
Keyword(s):  
Economic Analysis ◽  
Government Policy ◽  
Wood Species ◽  
Local Governments ◽  
Formal Education ◽  
Forest Products ◽  
Timber Species ◽  
Full Time ◽  
Percentage Frequency ◽  
Ogun State

This study involved the economic analysis of different wood species in major sawmills in Abeokuta, Ogun State Nigeria. Two stage design sampling techniques were employed for this study. Descriptive statistics and Cost and Returns were used in the data analysis. Result showed that 62.5% engaged in the business were males, 81.7% were in age group between 31-50years, 48.3% had no formal education, and 88.3% entered into the business through apprenticeship and are mostly full-time. The result also revealed that 95.83% of the saw millers or plank sellers obtain their timber from the private forest and they mostly buy per species i.e. per tree. Moreover, among the timber species that were common in the saw mills include, Albizia coriaria (ayinre) has the highest percentage frequency of 66.7%, Anogeissus leiocarpus (orin dudu) has 44.2%, Cleistopholis sp. (okedo) 32.5% and Musanga cecropioides (aga) 1.7% with the least percentage frequency. Average girth sizes of timber species in sawmill, ranged from 3.00cm- 5.60cm and the average number of plank ranged from 6-29. The business could be seen as profitable, as the cost analysis revealed the average profit for each sawmill per month  in Abeokuta North, Odeda and Abeokuta South Local Governments’ Areas to have these profits (₦982,893.75, ₦790,083.524 and ₦790,083.524) respectively. It was recommended that government policy should be reviewed against illegal felling and over-exploitation of timber by imposing/enacting stiffer penalty or law to illegal feller. Government policy should also encourage individual plantation establishment to ensure continuity of forest products for posterity.  

scholarly journals Heat-Treated Wood as a Substrate for Coatings, Weathering of Heat-Treated Wood, and Coating Performance on Heat-Treated Wood

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Vlatka Jirouš-Rajković ◽  
Josip Miklečić
Keyword(s):  
Heat Treatment ◽  
Wood Species ◽  
Treated Wood ◽  
Wood Properties ◽  
Treatment Method ◽  
Coating Performance ◽  
Treatment Processes ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Trade Names

Heat treatment is a method of wood modification with increasing market acceptance in Europe. The major patented European commercial heat treatment processes have trade names ThermoWood, Platowood, Retiwood, Le Bois Perdure, and Oil-Heat-Treated Wood (OHT). To what extent modification of wood affects the resistance of wood to weathering is also an important aspect for wood applications, especially where appearance is important. Unfortunately, heat-treated wood has poor resistance to weathering, and surface treatment with coatings is required for both protection and aesthetic reasons. As a substrate for coating, heat-treated wood has altered characteristics such as lower hygroscopicity and liquid water uptake and changed acidity, wettability, surface free energy, and anatomical microstructure. Various wood species, heat treatment method, treatment intensity, and treatment conditions exhibited a different extent of changes in wood properties. These altered properties could affect coating performance on heat-treated wood. The reported changes in acidity and in surface energy due to heat treatments are inconsistent with one another depending on wood species and temperature of the treatments. This paper gives an overview of the research results with regards to properties of heat-treated wood that can affect coating performance and weathering of uncoated and coated heat-treated wood.

scholarly journals Coating Performance on Exterior Oil-Heat Treated Wood

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 225 ◽  
Author(s):  
Mojgan Nejad ◽  
Mahdi Dadbin ◽  
Paul Cooper
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
Color Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Average Moisture Content ◽  
Southern Pine ◽  
Coating Performance ◽  
Spruce Wood ◽  
Heat Treated

Thermal modification and the degree of improved properties from the treatment depend on wood species and treatment parameters. Southern yellow pine and spruce are two wood species commonly used for decking, fences, and siding in North America. This study evaluated coating performance when applied on oil-heat-treated Southern pine and spruce wood samples. Moisture content, color, and gloss changes of samples were analyzed before weathering and then after each month for the first three months and then every six months during 18 months of natural weathering exposure in Toronto, Canada. The results showed that coated heat-treated woods had lower moisture uptake, lower color change, and overall better appearance ranking than coated-untreated wood samples. Coated-spruce wood samples had lower checking and splitting, and in general, much better performance than coated-Southern pine treated samples. Notably, the average moisture content of treated spruce wood samples was significantly lower than that of Southern pine, which explains lower checking and improved coatings’ appearance.

Developing deep learning models to automate rosewood tree species identification for CITES designation and implementation

Holzforschung ◽  
2020 ◽  
Vol 74 (12) ◽  
pp. 1123-1133 ◽  
Author(s):  
Tuo He ◽  
Yang Lu ◽  
Lichao Jiao ◽  
Yonggang Zhang ◽  
Xiaomei Jiang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Wood Species ◽  
Cost Effective ◽  
Timber Species ◽  
Learning Models ◽  
Field Screening ◽  
Anatomical Features ◽  
Wild Fauna ◽  
Parameter Configuration ◽  
Feature Visualization

AbstractThe implementation of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to combat illegal logging and associated trade necessitates accurate and efficient field screening of wood species. In this study, a total of 10,237 images of 15 Dalbergia and 11 Pterocarpus species were collected from the transverse surfaces of 417 wood specimens. Three deep learning models were then constructed, trained, and tested with these images to discriminate between timber species. The optimal parameters of the deep learning model were analyzed, and the representative wood anatomical features that were activated by the deep learning models were visualized. The results demonstrated that the overall accuracies of the 26-class, 15-class, and 11-class models were 99.3, 93.7, and 88.4%, respectively. It is suggested that at least 100 high-quality images per species with minimum patch sizes of 1000 × 1000 from more than 10 wood specimens were needed to train reliable and applicable deep learning models. The feature visualization indicated that the vessel groupings and axial parenchyma were the main wood anatomical features activated by the deep learning models. The combination of the state-of-the-art deep learning models, parameter configuration, and feature visualization provide a time- and cost-effective tool for the field screening of wood species to support effective CITES designation and implementation.

scholarly journals Shelling of Growth Rings at Softwood Surfaces Exposed to Natural Weathering

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 862
Author(s):  
Lukie H. Leung ◽  
Philip D. Evans
Keyword(s):  
Growth Ring ◽  
Inverse Correlation ◽  
Natural Weathering ◽  
Woody Tissue ◽  
Growth Rings ◽  
Western Larch ◽  
Wood Surfaces

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.

Copper and aluminium deposition by cold-plasma spray on wood surfaces: effects on natural weathering behaviour

2016 ◽  
Vol 75 (3) ◽  
pp. 315-324 ◽  
Author(s):  
P. Gascón-Garrido ◽  
N. Mainusch ◽  
H. Militz ◽  
W. Viöl ◽  
C. Mai
Keyword(s):  
Plasma Spray ◽  
Cold Plasma ◽  
Natural Weathering ◽  
Wood Surfaces ◽  
Weathering Behaviour
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