Guide · Materials
Why 2.70 g/cm³ is wrong for production
Freshman physics often treats aluminum as a single number. Production does not. Alloy density spans roughly 2.64–2.85 g/cm³. Using 2.70 everywhere injects silent error into weight quotes, freight, and material cost.
Typical handbook densities
| Alloy | Series | ρ (g/cm³) | Note |
|---|---|---|---|
| 1100 | 1xxx | 2.71 | Commercially pure |
| 2024-T3 | 2xxx | 2.78 | Aerospace Al-Cu |
| 5083-H116 | 5xxx | 2.66 | Marine Mg alloy |
| 6061-T6 | 6xxx | 2.70 | General fabrication |
| 7075-T6 | 7xxx | 2.81 | High strength Zn |
The 5.6% trap
5083-H116 (~2.66) and 7075-T6 (~2.81) differ by about 5.6%. On a 500 kg quote that is tens of kilograms and real money — before kerf and scrap.
AluCalc profile mass uses alloy-specific density from the materials database (ASTM B209 / EN 573 families), then optionally adds kerf, nesting efficiency, and price per kg for a preliminary production quote.
Always confirm
Handbook values are for preliminary engineering. Production quotes should use mill certificates and supplier prices. Kerf depends on process, thickness, and shop setup.