Fused Deposition Modelling (FDM) three-dimensional printing technology, with its high precision and design flexibility, offers a novel approach for reconstructing missing parts and producing temporary replicas of historical artefacts in museum contexts. This study evaluated the colour and structural stability of four widely available filaments in the Iranian market — polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), polyamide (PA), and polyethylene terephthalate glycol (PETG) — under accelerated ultraviolet (UV) ageing for 288 hours according to ASTM D4587-11. Prior to ageing, the chemical structure of the polymers was characterised using Fourier-transform infrared spectroscopy (FTIR). Colorimetric analysis (CIE L*a*b*) revealed that PLA exhibited the smallest colour change (ΔE), whereas ABS displayed the largest. Post-ageing FTIR spectra confirmed the formation of carbonyl peaks in PLA, ABS, and PETG, indicating photo-oxidative degradation; no such peak was observed in PA, demonstrating its superior structural stability. PLA is recommended for temporary museum applications owing to its excellent colour stability, while PA is preferred for components requiring high structural durability. ABS was deemed unsuitable due to pronounced colour shifts. Adhering to established conservation ethics, this research highlights the potential of FDM filaments in cultural heritage preservation, provided environmental conditions are rigorously controlled. The results indicate that polyamide (PA), due to its relative structural stability, and PLA, due to its minimal colour change, represent the optimal choices for reconstructing missing fragments or fabricating temporary supports for museum objects