Materials / Compare
Plastic PETG vs. Zinc Zamak 3
Compare Plastic PETG 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 | 46.2MPasourcetypical | 221MPasourcetypical4.78x stronger |
| Ultimate tensile strength | 46.2MPasourcetypical, peak stress (= stress at yield) | 283MPasourcetypical |
| Flexural strength | 78.9MPasourcetypical | not sourced |
| Elongation at break | 7.6%sourcetypical | 10%sourcetypical, in 2 in. |
| Young's modulus (stiffness) | 1.94GPasourcetypical | 85.5GPasourcetypical44.1x stiffer |
| Density | 1,270kg/m³sourcetypical5.2x lighter | 6,600kg/m³sourcetypical |
| Strength to weight | 36.4kN·m/kg9% higher | 33.5kN·m/kg |
| Stiffness to weight | 1.53MN·m/kg | 13MN·m/kg8.48x higher |
| Poisson's ratio | not sourced | 0.27sourcetypical, Zamak 3 hot-chamber die cast |
| Shear modulus | not sourced | 33.7GPa |
| Bulk modulus | not sourced | 62GPa |
| Speed of sound | 1,236m/s | 3,599m/s |
| Thermal | ||
| Thermal conductivity | 0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 113W/m·Ksourcetypical |
| Thermal expansion | 51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical | 27.4µm/m·Ksourcetypical |
| 100 mm part over a 50 °C swing | 255µm growth | 137µm growth1.86x less |
| Specific heat | 1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed) | 419J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.127mm²/s | 40.9mm²/s321x faster |
| Thermal shock resistance | not sourced | 7,782W/m |
| Melting point | not sourced | 381–387°Csourcemelting range |
| Glass transition | 77.4°Csourcetypical | not sourced |
| Max service temperature | 76.2°CsourceHDT 0.455 MPa (printed specimens) | not sourced |
| Values for | Ultimaker PETG, 3D-printed specimens, XY (flat); Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS v1.00, April 29, 2022. | 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.
Plastic PETG is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic PETG stronger than Zinc Zamak 3?
Zinc Zamak 3 is stronger: its yield strength is 221 MPa against 46.2 MPa for Plastic PETG (4.78x).
Which is lighter, Plastic PETG or Zinc Zamak 3?
Plastic PETG is lighter: 1,270 kg/m³ against 6,600 kg/m³ for Zinc Zamak 3.
Which is stiffer, Plastic PETG or Zinc Zamak 3?
Zinc Zamak 3 is stiffer: Young's modulus 85.5 GPa against 1.94 GPa for Plastic PETG, so the same part in Zinc Zamak 3 deflects less under the same load.
Which is lighter for the same job, Plastic PETG or Zinc Zamak 3?
For the same stiffness or strength: Plastic PETG 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 PETG | Zinc Zamak 3 |
|---|---|---|
| Stiff rod or tie (tension) | 8.48x heavier | lighter |
| Stiff beam (bending) | 28% heavier | lighter |
| Stiff panel or plate | lighter | 47% heavier |
| Strong rod or tie | lighter | 9% heavier |
| Strong beam | lighter | 1.83x heavier |
| Strong panel or plate | lighter | 2.38x 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 PETG or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 0.21 W/m·K for Plastic PETG.
Which expands less with temperature?
Zinc Zamak 3 expands less: 27.4 µm/m·K against 51 µm/m·K for Plastic PETG.