Epoxy vs BMI vs Phenolic Carbon Fiber Resin: Which Matrix Your Part Actually Needs
Carbon fiber is the reinforcement. The resin decides heat resistance, flame behavior and repairability.
Epoxy: most common, 120–180°C service, good balance, autoclave/prepreg friendly
BMI (bismaleimide): 200°C+ class, aerospace engine-adjacent structures, higher cost, brittle if not toughened
Phenolic: low smoke, low toxicity, flame-retardant, rail/marine/fire-critical parts, lower mechanical ceiling than epoxy
Cyanate ester / polyimide: radar-transparent or very high-temp niches, not everyday industrial
Buyer mistake: ask for "aerospace carbon" and only check fiber grade. If the resin can't hold glass-transition temperature under your service load, T800 won't save you.
Ask suppliers: resin brand/system, Tg, post-cure cycle, flame standard (UL94 / EN45545 / FAR25.853), and whether the cure route matches the resin.
Need a carbon part sized by resin system, not by catalog? Send your service temperature, load direction and flame requirement - we propose resin, layup and cure process.
