Materials / Compare
Plastic Polycarbonate vs. Zinc Zamak 3
Compare Plastic Polycarbonate vs. Zinc Zamak 3 strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 65MPasourcetypical, tensile yield | 221MPasourcetypical |
| Ultimate tensile strength | 65MPasourcetypical, stress at break | 283MPasourcetypical |
| Flexural strength | 97MPasourcetypical, flexural strength | not sourced |
| Elongation at break | 125%sourcetypical, strain at break | 10%sourcetypical, in 2 in. |
| Young's modulus (stiffness) | 2.4GPasourcetypical | 85.5GPasourcetypical35.6x stiffer |
| Density | 1,200kg/m³sourcetypical5.5x lighter | 6,600kg/m³sourcetypical |
| Strength to weight | 54.2kN·m/kg1.62x higher | 33.5kN·m/kg |
| Stiffness to weight | 2MN·m/kg | 13MN·m/kg6.48x higher |
| Poisson's ratio | 0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1) | 0.27sourcetypical, Zamak 3 hot-chamber die cast |
| Shear modulus | 0.87GPa | 33.7GPa38.7x stiffer in shear |
| Bulk modulus | 3.33GPa | 62GPa |
| Speed of sound | 1,414m/s | 3,599m/s |
| Thermal | ||
| Thermal conductivity | 0.2W/m·Ksourcetypical, through-plane, 23 C | 113W/m·Ksourcetypical |
| Thermal expansion | 65µm/m·Ksourcetypical, 23-55 C, parallel and normal | 27.4µm/m·Ksourcetypical |
| 100 mm part over a 50 °C swing | 325µm growth | 137µm growth2.37x less |
| Specific heat | 1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766 | 419J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.142mm²/s | 40.9mm²/s288x faster |
| Thermal shock resistance | 51.7W/m | 7,782W/m151x more resistant |
| Melting point | not sourced | 381–387°Csourcemelting range |
| Glass transition | 144°Csourcetypical, DSC 10 C/min | not sourced |
| Max service temperature | 125°CsourceUL 746B RTI, tensile strength, 1.5 mm | not sourced |
| Values for | Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical values | Zamak 3 (ASTM B86 die cast), Nathan Trotter (zinc alloy producer) technical data sheet, typical values |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is Plastic Polycarbonate stronger than Zinc Zamak 3?
Zinc Zamak 3 is stronger: its yield strength is 221 MPa against 65 MPa for Plastic Polycarbonate (3.4x).
Which is lighter, Plastic Polycarbonate or Zinc Zamak 3?
Plastic Polycarbonate is lighter: 1,200 kg/m³ against 6,600 kg/m³ for Zinc Zamak 3.
Which is stiffer, Plastic Polycarbonate or Zinc Zamak 3?
Zinc Zamak 3 is stiffer: Young's modulus 85.5 GPa against 2.4 GPa for Plastic Polycarbonate, so the same part in Zinc Zamak 3 deflects less under the same load.
Which is lighter for the same job, Plastic Polycarbonate or Zinc Zamak 3?
For the same stiffness or strength: Plastic Polycarbonate is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Zinc Zamak 3 is lighter for a stiff rod or tie (tension), stiff beam (bending).
| Part that must be | Plastic Polycarbonate | Zinc Zamak 3 |
|---|---|---|
| Stiff rod or tie (tension) | 6.48x heavier | lighter |
| Stiff beam (bending) | 9% heavier | lighter |
| Stiff panel or plate | lighter | 1.67x heavier |
| Strong rod or tie | lighter | 1.62x heavier |
| Strong beam | lighter | 2.43x heavier |
| Strong panel or plate | lighter | 2.98x heavier |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, Plastic Polycarbonate or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 0.2 W/m·K for Plastic Polycarbonate.
Which expands less with temperature?
Zinc Zamak 3 expands less: 27.4 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.