<p>Surface deformations are a significant concern in the furniture and industrial coating sectors, as they affect both aesthetics and functionality, making it essential to enhance the durability and longevity of coatings. In this context, the study aims to develop coatings with improved surface properties by synthesizing impact-resistant organic binders to prevent surface deformations. Accordingly, efforts have been made to enhance the impact resistance of polyurethane-based wood coatings. In the synthesis studies, alkyd resins were synthesized using sunflower fatty acid or castor oil with oil lengths ranging from 28 to 46% and hydroxyl values between 4.0 and 4.9, in order to evaluate the effect of both oil length and the type of oil or fatty acid on the elasticity of the resin. Alkyd resins with different oil lengths were synthesized using phthalic anhydride (PA), sunflower fatty acid (SFA), castor oil (CO), and pentaerythritol (PN). In the resin synthesis process, equivalent amounts of resin and hardener were mixed and applied to various surfaces using an applicator to form films. The touch-dry and stack-dry times of these films were determined. Subsequently, physical surface coating tests, including gloss, impact resistance, pencil hardness, and pendulum hardness tests, were conducted. The test results revealed that the varnish (VCOA46) formulated with castor oil-modified alkyd resin with a 46% oil length (COA46) exhibited superior impact resistance. Additionally, the coating film containing COA46 demonstrated a pencil hardness of 3B, a pendulum hardness of 128 seconds, an adhesion strength of Class 1, a gloss value of 38 gloss units, and higher impact resistance compared to other formulations. These findings suggest that castor oil-modified alkyd resins with optimized oil length can significantly enhance the impact resistance and overall performance of polyurethane-based wood coatings, making them promising candidates for industrial applications.</p>