Authors Susilo AdiwidyantoFaculty of Engineering, Department of Mechanical Engineering, Diponegoro University, IndonesiaYusuf UmardaniFaculty of Engineering, Department of Mechanical Engineering, Diponegoro University, IndonesiaAgus SuprihantoFaculty of Engineering, Department of Mechanical Engineering, Diponegoro University, IndonesiaFernando PandianganFaculty of Engineering, Department of Mechanical Engineering, Diponegoro University, Indonesia Abstract This study explores the influence of talc as a reinforcing filler on the mechanical properties of four types of RTV silicone rubber—RTV 497, RTV 52, RTV 10A, and RTV 00A. Specimens were fabricated with varying talc contents (5%, 10%, 15%, 20%, 25%, and 30% by weight) and subjected to tensile and compressive testing in accordance with ASTM standards. The mechanical performance, particularly tensile and compressive strength, improved significantly with increasing talc content up to an optimal threshold. The findings highlight the potential of talc to enhance silicone rubber-based composites for applications such as orthotic footbeds and other load-bearing structures. Keywords Silicone rubber RTV talc mechanical properties tensile strength compressive test Citation of this Article Susilo Adiwidyanto, Yusuf Umardani, Agus Suprihanto, & Fernando Pandiangan. (2025). Effect of Talc Addition on the Mechanical Properties of RTV Silicone Rubber: Comparative Study of RTV 497, RTV 52, RTV 10A, and RTV 00A. Current Journal of Engineering and Science Research. 2(5), 7-12. Article DOI: https://doi.org/10.47001/CJESR/2025.205002 Licence Copyright (c) 2026 Current Journal of Engineering and Science Research. This work is licensed under a Creative Commons Attribution Non Commercial 4.0 International Licence. References Ammar, M. R., Mohd Ishak, Z. A., & Mahmud, H. N. (2017). Talc as reinforcing filler in polypropylene compounds: Effect on morphology and mechanical properties. 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