Fan blades are the heart of any axial fan — and the material they are made of decides where the fan can work, how long it lasts and how much it costs to run. Here is the practical comparison we give our customers.
Cast aluminium (LM6 / A356)
The classic industrial choice. Aluminium impellers are dimensionally stable, corrosion-resistant enough for most indoor duty, and — crucially — the only option for fire-rated smoke-extraction fans, where blades must survive up to 400°C. High-speed mining and process fans are almost always aluminium for balance quality. At SINDFAN we cast A356/LM6 in our own foundry and X-ray inspect die-cast impellers to ASTM E155.
GRP (glass-reinforced plastic)
Hand-laid or RTM GRP blades excel where corrosion and chemicals attack metal: marine engine rooms, wastewater, chemical plants and agricultural buildings. GRP is light, quiet and can be moulded into complex aerodynamic shapes. Temperature ceiling is about +70°C continuous — fine for ventilation, wrong for hot exhaust.
Nylon66 (GRN)
Injection-moulded nylon66 blades bridge the gap: tough, fatigue-resistant and happy up to +150°C, which covers hot exhaust and heat-recovery applications. Add anti-static filler (GRN-ATI) and the impeller is safe to run in explosion-risk zones when paired with an Ex motor.
Decision table
| Application | Blade material |
| Smoke extraction / fire-rated (400°C) | Cast aluminium LM6 |
| Marine / chemical / agriculture | GRP |
| Hot exhaust up to 150°C | Nylon66 GRN |
| Explosion-risk zones | Anti-static GRN-ATI + Ex motor |
| General ventilation, high speed | Cast aluminium |
Every material changes the rotor weight, which changes the balance grade you can hold. That is one more reason to buy the impeller and the balancing from the same factory. Tell us your environment — we will recommend the material, not just the price.