The aim of the present study was to determine the surface roughness of heat-treated Scots pine (Pinus sylvestris L.), Eastern beech (Fagus orientalis L.), Uludağ fir (Abies bornmülleriana Mattf.), and sessile oak (Quercus petraea L.) wood material samples following planing by the cutters of a horizontal milling machine. The samples that were heattreated at 140 ºC or 160 ºC for 3, 5, or 7 hours were then processed by star blades or razor blades, which are the most frequently used blade types in a milling machine. The surface roughness of the samples was determined by a touch (spined) scan device (TIME TR200), as indicated by the ISO 4287 principle. The results of the study indicate that heat treatment decreases the surface roughness value of the wood material and a significant difference in surface roughness cannot be detected between planing using the razor blade or the star blade.

No abstract

Heat treatment is known to improve the stability and durability of various woods. However, in the process some surface properties are changed. This paper reports the changes in surface properties such as color, glossiness, pendulum hardness, and surface adhesion on coated heattreated and untreated beech wood. The wood was coated with an epoxy acrylic resin sealer followed by a polyacrylic-based resin varnish that is normally applied on parquet with single and double layers according to the manufacturer's recommendations. The results showed that in relation to color parameters, the lightness decreased while a* increased in response to heat treatment. This was followed by a decrease in the redness (a*) and a decrease in yellow (b*) with the intensity of the treatment. There was an initial increase in the glossiness but it decreased later on with the severity of the treatment. The hardness and adhesion also decreased with the severity of the treatment for beech coated with single and double layers. The wood surface properties depended on the treating time and the temperature of the treatment.

In the last few years there has been an increased demand to change the natural color of valuable hardwoods without chemicals for use mainly in indoor parquet floors. In this study, wood samples from oak (Quercus petraea L.), one of the most used species for parquet, were heat treated (ThermoWood method) at 190 °C for 2 h and at 212 °C for 1 and 2 h. Untreated and heat treated wood surfaces were coated following two different applications: type 1, with a single layer of sealer (50 g/m2) and type 2 with two layers (35 g/m2) using a nanolacke varnishing system. The objective of this study was to investigate surface properties including adhesion, glossiness, pendulum hardness, and color (L*, a*, b*, ΔE*, ΔL*, Δa*, and Δb*). With heat treatment the lightness decreases, and its decrease is higher for higher temperatures and treatment times. Type 2 coated wood presented a slightly lower lightness decrease. The experiment showed a slight increase followed by a decrease in redness (lower a*) and a clear decrease in the yellow tone (b*). The total color variation increased with the intensity of the treatment, while the glossiness decreased (more for Type 1 coated wood). The adhesion strength and surface hardness decreased with the heat treatment in both the Type 1 and Type 2 coated wood samples. The decrease in adhesion was higher for Type 2, reaching 67%, while the decrease in surface hardness reached about 18%.

Bu çalışmada, 212°C'de 1 saat ve 2 saat süreyle ısıl işlem (ThermoWood metot, Novawood Fabrikası, Gerede-Bolu, Türkiye) görmüş dişbudak (Fraxinus excelsior), kayın (Fagus orientalis L.), akçaağaç (Acer trautvetteri Medw.) ve kızılçam (Pinus resinosa) odunu türlerinin renk ve parlaklık değerleri incelenmiştir. Isıl işlemden sonra, bu ısıl işlem görmüş ağaç türlerinin renk ve parlaklık değerleri ısıl işlem görmemiş örnekler ile kıyaslanmıştır. Test sonuçlarına göre; ΔE* değerleri artmıştır. Isıl işlem süresinin artması ile dişbudak, kayın ve akçaağaç odunlarında L* ve b* parametreleri azalmıştır. a* parametresi kızılçam ve akçaağaç odunlarında ısıl işlem süresinin artması ile artmıştır. Isıl işlem süresinin artması ile 85°'de paralel ve dik parlaklık değerleri kızılçam ve akçaağaç odunlarında artmıştır. Isıl işlem sıcaklık ve süreleri odun örneklerinde renk ve parlaklık değerlerini değiştirmiştir.

Heat treatment is one of the methods of wood modification and it is known that it changes the technological properties of wood. In this study, the determination of the colour and glossiness values on the wood species which heat treated according to ThermoWood method (at 212 o C for 1 hour and 2 hours) that is obtained from, zebrano (Microberlinia brazzavillensis), sapelli (Entandrphragma cylindrocum) and merbau (Intsia bijuga) was aimed. The colour and glossiness values were determined on samples prepared from different tree species. Lightness (L*) and yellow colour (b*) tone values were decreased by heat treatment. The glossiness values of the test specimens were also changed by heat treatment application. According to these results; the highest total colour difference value (ΔE*) was determined on merbau samples, the lowest total colour difference value (ΔE*) was determined on sapelli samples. According to obtained data; it can be said that the colour and glossiness values of wood of zebrano, sapelli and merbau was affected by heat treatment.

Heat treatment is an industrial application that changes the physical, mechanical and chemical properties of wood. In addition, the smell, color and surface roughness of the heat treated wood also varies. The objective of this study is to investigate surface roughness properties (R a , R z and R q ) of heat treatment and untreated some wood types. In this study, wood specimens prepared from Scotch pine (Pinus sylvestris L.), oak (Quercus petreae L.) and beech (Fagus orientalis L.) wood species were heat-treated according to ThermoWood ® method at 212 o C for 1 hour and 2 hours in Bolu -Gerede, Turkey. Caliber sanding machine with 180 grinding were applied untreated and heat-treated specimens after heat treatment. Surface roughness parameters (R a , R z and R q ) according to ISO 4287 (1997) standard were determined for all samples. According to obtained data, it was observed that the R a , R z and R q parameters decreased when the heat treatment time increased. It was determined that the surface roughness of all wood materials was changed by the applied heat treatment process.