Maker’s Muse Tests 8 3D Filaments, Finds TPU and PETG Resist Fire Best

Q: If high-heat materials burn aggressively, what unexpected everyday filament is actually your safest bet against fire?

The safest unexpected everyday filament is standard TPU, with PETG close behind. Maker’s Muse’s flame test found that regular TPU was the least flammable of the common consumer filaments tested. Even under a blowtorch, it mostly softened and melted rather than sustaining ignition. That makes it a notably safer choice against accidental flame exposure than many “high-heat” engineering plastics. PETG also performed well, especially black PETG, which was difficult to ignite and ranked among the safer practical options. By contrast, ABS, ASA and HIPS — materials often chosen for better heat resistance in normal use — burned aggressively with a sooty yellow flame once lit. The test showed that heat tolerance and fire safety are not the same thing. The broader lesson is that formulation matters as much as the polymer family. PLA variants behaved very differently: some ignited easily, while HTPLA resisted burning and self-extinguished. Additives, pigments and fillers can significantly change fire behavior, so a material label alone is not enough to predict risk. For everyday users choosing a common filament with lower fire hazard, standard TPU is the best bet, and PETG is a strong rigid-material alternative. For genuinely fire-critical parts, though, the safer path is to use a filament with a verified flammability rating such as UL 94 for the exact formulation and thickness, rather than relying on generic material reputation.

1 articles · Updated · Hackaday · Aug 12

Eight common 3D-print materials showed sharply different fire behavior in Maker’s Muse burn tests, with regular TPU resisting ignition even under a blowtorch and PETG also proving hard to light.
PLA samples burned readily overall, but additives appeared to matter: Prusa Galaxy Black PLA needed a blowtorch to ignite, while HTPLA self-extinguished after direct flame exposure.
ABS, ASA and HIPS burned aggressively with sooty yellow flames, and foam TPU was the most intense burner once ignited despite standard TPU’s strong resistance.
The results suggest filament choice can materially change fire risk for printed parts exposed to open flame or high heat, with PETG and regular TPU emerging as safer options than PLA or ABS.