WOOD RESEARCH Volume 61, Number 6, 2016
Suleyman Ustun, Ergun Baysal, Turkay Turkoglu, Hilmi Toker, Cevdet Sacli, and Huseyin Peker

Surface characteristics of scots pine treated with chemicals containing some copper compounds after weathering

In this study, it was aimed to investigate surface hardness, gloss, and color changes of Scots pine treated with chemicals containing some copper compounds after six months weathering. Adolit KD-5 (AD KD-5), celcure AC-500 (CAC-500), and wolmanit CX-8 (WCX-8) were used as impregnation chemicals containing copper compounds. Scots pine wood specimens were treated with 2 % aqueous solution of chemicals according to ASTM D1413-07e1 (2007) standard. Results showed that while surface hardness and gloss values of untreated Scots pine wood specimens were decreased after weathering, they increased treated Scots pine wood specimens after weathering. The decrease in L* of untreated and treated wood indicates that the specimens became darker after weathering. While weathering caused less green and less yellow for untreated control specimen, it caused less red and less yellow for treated wood. Treated Scots pine wood specimens showed better color stability compared to untreated Scots pine after weathering. In terms of surface hardness, gloss, and color stability values CAC-500 treated Scots pine gave the best results after weathering.

WOOD RESEARCH Volume 61, Number 4, 2016
Eliška Oberhofnerová and Miloš Pánek

Surface wetting of selected wood species by water during initial stages of weathering

Currently, the trend of using untreated wood elements in the exterior is becoming more progressive. The rainwater nevertheless needs to be recognized as an important factor increasing photo-degradation of wood and causing other damages as splits, cracks and deformations. The aim of this work is to determine the influence of initial stages of weathering on wetting properties of wood surfaces evaluated by the contact angle measurements using goniometer Krüss DSA 30E. Nine wood species were tested during 12 months of weathering: spruce, larch, pine, Douglas fir, oak, black locust, maple, alder and poplar. The lower decrease of the contact angle of water drop was observed on maple, alder and black locust surfaces, which predicts higher durability and slower degradation during weathering. On the contrary, the higher decrease of contact angle and higher hydrophilicity of wood surfaces was observed on all softwoods and oak and poplar as well.

WOOD RESEARCH Volume 62, Number 6, 2017
Mustafa Kucuktuvek, Ergun Baysal, Turkay Turkoglu, Huseyin Peker, Ahmet Gunduz, and Hilmi Toker

Surface characteristics of scots pine wood heated at high temperatures after weathering

This study was conducted to investigate some surface properties of wood specimens of heat treated Scots pine (Pinus sylvestris L.) after weathering such as surface hardness, surface roughness, gloss, and color changes. Heat treatment of Scots pine wood was carried out by hot air in an oven for 1, 2, and 3 hours at 210, 220, and 230°C. The results showed that generally surface hardness losses of heat treated Scots pine wood were lower than that of un-heated Scots pine wood after weathering. Heat treated Scots pine wood gave smooth surface after weathering. Except for heat treatment at 230°C for 1 and 2 hours, heat treatment resulted in better glossiness compared to un-heated Scots pine wood after weathering. According to the test results, while heat treated Scots pine wood become lighter after weathering, un-heated wood become darken after weathering. In general, heat treated wood surface to become reddish and yellowish after weathering.

WOOD RESEARCH Volume 62, Number 5, 2017
Osman Emre Özkan, Ali Temiz, and Hasan Vurdu

Effects of heat treatment on Turkish fir wood properties

In this study, Turkish fir wood (Abies nordmanniana subsp. bornmulleriana) was subjected to two heat treatment process with varying temperatures (150, 180 and 200°C) and durations (2, 4 and 6 h). Some properties of the heat treated Turkish fir wood; mass change, water absorption, volumetric swelling, bending strength, modulus of elasticity (MOE), compression strength parallel to grain, color change and surface roughness have been tested and evaluated by statistical analysis. Consequently, volumetric swelling and water absorption values of the heat treated wood samples reducing. Bending strength, modulus of elasticity and compression strength parallel to grain values were decreased by heat treatment at high temperatures. Additionally, color change and surface roughness values of heat treated wood decreased with weathering compared to those of control samples.

WOOD RESEARCH Volume 63, Number 5, 2018
Saban Kart, Ergun Baysal, Turkay Turkoglu, Mustafa Kucuktuvek, Huseyin Peker, Caglar Altay, Ahmet Gunduz, and Hilmi Toker

The effect of natural weathering on change in the color of heat treated and varnished scots pine and oriental beech woods

This study was designed to investigate color changes of heat treated and varnished Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis L.) after 3 months of weathering. Heat treatment of Oriental beech and Scots pine wood was carried out by hot air in an oven for 1, 2, and 3 hours at 205, 215, and 225°C. After heat treatment, wood specimens were varnished using a polyurethane varnish (PV) and cellulosic varnish (CV). The results of study showed that heat treatment generally caused decrease of lightness of both wood specimens before weathering. In general, while heated and PV coated Scots pine and Oriental beech wood surfaces turned to reddish and yellowish, heated and CV coated Scots pine and Oriental beech wood surfaces turned to reddish and bluish after weathering. The total color changes of heated and varnished both wood specimens were lower than only varnished both wood specimens after weathering.

WOOD RESEARCH Volume 65, Number 3, 2020
Candan Kus Sahin, Mehmet Topay, and Ahmet Ali Var

A study on suitability of some wood species for landscape applications: Surface color, hardness and roughness changes at outdoor conditions

In this study, each of the commonly used two types of woods (softwood and hardwood) from five species was studied. All wood species show a systematic trend to change to higher values of surface roughness with natural weathering progress. The Black pine, Calabrian pine and beech wood samples show a more or less smooth trend, whereas basswood gives the highest surface roughness changes under all conditions. However, the hardwood species, except basswood, have higher hardness properties both initially and at the end of weathering process when compared to softwoods. The surface discoloration that occurs is clearly visible as a natural texturing. However, the degree of, and the pattern of texturing, may vary with different kinds of woods; the color changes also vary to some extent. It was revealed that the discoloration is strongly dependent on the botanical origin of wood species. The lower lightness changes (ΔL %) were found for all three pine species (16.2 to 37.2%) when compared to fir (54.9%) and spruce samples (91.8%). The Scotch pine wood showed highest values for the contribution of red color initially and low redness change on the surface after the weathering process, among the other softwood species.

WOOD RESEARCH Volume 64, Number 1, 2019
Saban Kart, Ergun Baysal, Mustafa Kucuktuvek, Turkay Turkoglu, Hilmi Toker, Caglar Altay, Cihan Cibo, and Huseyin Peker

Some surface characteristics of varnished thermowood after weathering

This study was designed to investigate some surface characteristics such as glossiness and surface roughness changes of varnished thermowood after six months of weathering. Thermal modification of Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis L.) wood were carried out by hot air in an oven for 1, 2, and 3 hours at 205, 215, and 225°C. After the modification process, wood specimens were varnished using a polyurethane varnish (PV) and cellulosic varnish (CV). The natural weathering process caused an increase in the surface roughness of the test specimens according to the test results. The Scots pine and Oriental beech test specimens which were heat treated and varnished gave more favorable results compared to only varnish test specimens after natural weathering in terms of surface characteristics such as surface roughness and glossiness. Generally, as the heat treatment time and temperature increase, it is observed that the surface characteristics of the Scots pine and Oriental beech wood specimens improve positively. According to the results of the tests, the samples varnished with polyurethane varnish gave better results in terms of surface roughness at the end of the natural weathering process, whereas the samples varnished with cellulosic varnish gave better results in terms of glossiness values.