*Arash Afshar, Dorina Mihut, David Carter, Barrett McDonald, Ryan McMillan, Mercer University, Atlanta, GA<br> The research is investigating the effectiveness of metallic coatings applied to 3 D printed polymers working in harsh environmental conditions. It is studying the improvement of flexural strength for coated structures before and after a cyclic environmental exposure to UV radiation, high temperature and moisture. The 3 D printed polymer specimens were manufactured by fused deposition modeling according to ASTM D790 standard and their mechanical properties were tested using a Mark-10 flexural testing equipment. The silver metallic coatings were deposited using DC high vacuum magnetron sputtering technique. The 3 D printed specimens were sequentially exposed to UV radiation, high temperature and moisture according to ASTM G154 standard using a Q-Lab QUV accelerated weathering tester. The metallic coating adhesion before and after the testing was evaluated using Scanning Electron Microscopy (SEM) and by using the ISO 2409 standard. The crystalline structure of the metallic coatings was analyzed using X-ray Diffraction technique. The metallic thin films improved the surface resistance of the substrate materials and enhanced the mechanical behavior of samples exposed to harsh environmental conditions.