PEBA Filament Burns Longer and Hotter Than Expected in Burn Test

PEBA surprised the burn test

Maker's Muse ran a fresh burn test on PEBA flexible filament and the results contradict the assumption that all soft filaments behave like safe, self-extinguishing TPU. When held to an open flame, PEBA burned longer and more aggressively than standard TPU, though it did not match the ferocious output of foamed TPU seen in an earlier test.

The experiment exposed PLA, PETG, ABS, ASA, TPU, PEBA, HIPS, and HTPLA to both an open flame and a blowtorch. PLA burned readily, PETG resisted ignition, and ABS and ASA produced sooty yellow flames. Among the flexible materials, regular TPU proved the most fire-resistant, requiring sustained torch heat to ignite at all. PEBA fell somewhere in the middle: it ignited more easily than TPU and kept burning after the flame source moved away.

PEBA's MSDS data from manufacturers like eSUN and Fillamentum lists the material as not flammable under normal conditions but capable of burning at high temperatures. The burn test puts that distinction into practical context. In a workshop fire, PEBA will feed a flame longer than TPU would.

The takeaways for home makers are straightforward. PETG and regular TPU remain the safest bets for functional parts that might see heat or sparks. If you are printing with PEBA for its flexibility and durability, treat it with the same caution you would give ABS or ASA: keep it away from hot ends, enclosed chambers without ventilation, and open flames. The material is useful, but it is not as forgiving as TPU in an emergency.