This study determined the impact of undertaking an initial treatment of oak wood by sealing its surface pores with epoxy resin, focusing on the durability of transparent coating systems when exposed outdoors. Throughout the exposure period, various parameters including color, gloss, surface wettability, and both macroscopic and microscopic surface evaluation were continuously monitored. The study involved two sets of samples: one set underwent the pretreatment, while the other did not. Subsequently, four coating systems were applied to the samples, comprising two solvent-based and two water-based coatings. The experiment was conducted over a period of two years, utilizing natural weathering methods within the premises of the Czech University of Life Sciences in Prague. The pretreatment with epoxy resin exhibited enhanced durability for all paint systems. The analysis showed a significant difference in gloss and color after 12 months of weathering exposure without any significant effect on surface wettability and sealing. However, after 24 months of the weathering exposure, no significant differences between the sealed and unsealed surface were observed. The most significant change in properties was noted for the water-based coatings used in coating systems number 3 and 4, and these coatings were rated as the best.

Cutting beech plywood using abrasive water jet (AWJ) technology represents a significant area of research due to increasing demands for precision, quality, and environmental sustainability in manufacturing processes within the woodworking industry. AWJ technology enables non-contact cutting of materials without causing thermal deformation or mechanical damage, which is crucial for preserving the structural integrity and mechanical properties of the plywood. This article investigates cutting beech plywood using technical methods using an abrasive water jet (AWJ) at 400 MPa pressure, with Australian garnet (80 MESH) as the abrasive material. It examines how abrasive mass flow rate, traverse speed, and material thickness affect AWJ lag, which in turn influences both cutting quality and accuracy. Measurements were conducted with power abrasive mass flow rates of 250, 350, and 450 g/min and traverse speeds of 0.2, 0.4, and 0.6 m/min. Results show that increasing the abrasive mass flow rate from 250 g/min to 350 g/min slightly decreased the AWJ cut width by 0.05 mm, while further increasing to 450 g/min caused a slight increase of 0.1 mm. Changes in traverse speed significantly influenced cut width; increasing the traverse speed from 0.2 m/min to 0.4 m/min widened the AWJ by 0.21 mm, while increasing it to 0.6 m/min caused a slight increase of 0.18 mm. For practical applications, it is recommended to use an abrasive mass flow rate of around 350 g/min combined with a traverse speed between 0.2 and 0.4 m/min when cutting beech plywood with AWJ. This balance minimizes jet lag and maintains high surface quality comparable to conventional milling. For thicker plywood, reducing the traverse speed closer to 0.2 m/min and slightly increasing the abrasive flow should ensure clean cuts without compromising surface integrity.

This article deals with cutting power during the plane milling of thermally treated and untreated silver birch (Betula pendula Roth.) wood. Thermal treatment was carried out at various temperatures of 160, 180, 210, and 240 °C. The cutting power was measured under various milling conditions, such as rake angle of tool (10°, 15°, 20°, 25°, and 30°), cutting speed (20, 40, and 60 m/s), and feed speed (4, 8, and 11 m/min). Thermal treatment had no clear impact on the cutting power. Treated wood at 160 and 180 °C had lower values of cutting power in comparison with untreated wood, while the opposite trend was observed at 210 and 240 °C. The results show that with increasing speed feed, there is an increase in cutting power, while the opposite effect was achieved by changing the cutting speed. The optimum values of cutting power were achieved at a 10° angle and a thermal treatment of 160 °C.

Wood is a natural material and is subject to degradation due to weather, UV radiation, and humidity. Wood is composed of many components. The basic structural elements of wood include cellulose, hemicellulose, and lignin. Furthermore, these are accompanying substances, which also include extractive substances. Specifically, these substances, together with lignin, have a negative effect on its life thanks to their chemical reactions, which are initiated mainly by UV radiation (so-called photodegradation). This study evaluates the effect of controlled degradation of extractives and lignin on the surface of the wood before the application of the coating system and also on its overall service life. Samples of larch wood (Larix decidua Mill.) were exposed to exterior natural influences in Prague (Czech Republic) according to EN 927–3 (2020) for 10 and 20 weeks. Subsequently, the samples were sterilized in an autoclave, due to possible contamination of the surface with fungi. The specimens were then treated with two oil–coating systems (V–420 and V–429). Subsequently, they were exposed to artificial aging in a UV chamber according to EN 927–6 (2019). Testing occurred at predetermined time intervals of 0, 1, 3, and 6 weeks, roughly corresponding to 0, 2, 6, and 12 months outdoors. The evaluated factors were the change in color, gloss, and surface wettability. The results showed a slightly positive effect of surface washout lasting ten weeks before applying the coating system.

Surface pretreatment significantly influences the hygroscopic behavior of wood, which in turn affects surface stability when exposed to variable climatic conditions. This study focuses on how different surface pretreatment methods impact the performance of protective coating applied on spruce wood (Picea abies (L.) Karst.) during one year of natural weathering. Samples were prepared using various surface treatments: milling and sanding with grit sizes P40, P80, and P120, respectively. Two types of coatings were applied: a solventborne coating (ADLER Pullex Plus-Lasur) and a waterborne coating (DColor FK 47 UV Protect). The samples were exposed for 12 months at an outdoor testing site in Suchdol, Czech. Surface properties were assessed through color changes in the CIE Lab* space, gloss measurements (ISO 2813), contact angle analysis, and visual inspection. The results showed that exposure to UV radiation and microbial activities led to the gradual degradation of the optical properties and aesthetic appearance of the wood. Surfaces with greater roughness preserved their aesthetic properties more effectively, indicating a higher absorption of the coating. Untreated wood exhibited low water repellency, while the coated surface demonstrated enhanced hydrophobicity. Notably, the waterborne coating showed a temporary increase in contact angle around the sixth month, indicating surface clogging by dust particles. In contrast, the solventborne coating had a rapid decrease in wettability during the first nine months. These findings suggested the importance of surface pretreatment and coating type in maintaining the long-term performance and aesthetic appearance for wood used in exterior conditions.

High-temperature drying can considerably improve drying efficiency. However, information on its impact on the mechanical properties of silver fir during industrial high-temperature drying remains limited. Elevated drying temperatures may induce changes in wood structure that can influence mechanical performance. This study evaluated the effect of high-temperature drying schedules based on industrially applied temperature levels (120 °C and 150 °C) on selected mechanical properties of silver fir (Abies alba Mill.). Wood samples were kiln-dried at 120 °C and 150 °C, conditioned to equilibrium moisture content, and tested for impact bending strength, tensile strength perpendicular to the grain, and Janka hardness. Because the experimental material originated from a single silver fir tree, the findings should be interpreted as describing responses within the investigated material rather than as population-level effects for silver fir. The results showed that drying at 150 °C was associated with a tendency toward reduced values of selected mechanical properties; however, the effect of drying temperature was not statistically significant for impact bending strength. ANOVA showed that specimen thickness significantly affected impact bending strength and Janka hardness, whereas drying temperature had a significant effect only on tensile strength perpendicular to the grain. The lowest mean values were observed in the β-150 group, with impact bending strength of 5.4 J·cm⁻² and tensile strength perpendicular to the grain of 2.3 MPa. The mean oven-dry density was 456.9 kg·m⁻³, while only weak relationships between density and mechanical properties were observed (r² = 0.023–0.178). This suggests that factors related to drying conditions may contribute to variability in mechanical performance beyond the effect of density alone. Thus, the effects of the investigated drying conditions were property-specific rather than consistently attributable to drying temperature. Within the investigated material, these results indicate that the optimization of high-temperature drying schedules should consider both drying parameters and variability in mechanical properties.