Materials / Compare
Glass vs. Plastic PLA
Compare Glass vs. Plastic PLA strength, stiffness, weight and thermal properties.
| Try it on a partA sample part to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | not given (tensile used) | 52.5MPasourcetypical |
| Ultimate tensile strength | 41MPasourcetypical mean surface tensile stress at fracture (MOR), 60 s load, weathered, 50% breakage probability | 52.5MPasourcetypical, peak stress (= stress at yield) |
| Flexural strength | 41MPasourcemean MOR (same value as tensile) | 96.8MPasourcetypical |
| Elongation at break | not sourced | 7.8%sourcetypical |
| Young's modulus (stiffness) | 72GPasourcetypical22.2x stiffer | 3.25GPasourcetypical |
| Density | 2,500kg/m³sourcetypical | 1,240kg/m³sourcetypical2.02x lighter |
| Strength to weight | 16.4kN·m/kg | 42.3kN·m/kg2.58x higher |
| Stiffness to weight | 28.8MN·m/kg11x higher | 2.62MN·m/kg |
| Poisson's ratio | 0.22sourcetypical | not sourced |
| Shear modulus | 29.5GPa | not sourced |
| Bulk modulus | 42.9GPa | not sourced |
| Speed of sound | 5,367m/s | 1,619m/s |
| Thermal | ||
| Thermal conductivity | 0.937W/m·Ksourcetypical at 75 F | 0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C |
| Thermal expansion | 8.3µm/m·Ksourcetypical, 75-575 F | not sourced |
| 100 mm part over a 50 °C swing | 41.5µm growth | not sourced |
| Specific heat | 880J/kg·Ksourcetypical at 75 F | 1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C |
| Heats up and cools (diffusivity) | 0.426mm²/s4.88x faster | 0.0874mm²/s |
| Thermal shock resistance | 50.1W/m | not sourced |
| Melting point | not sourced | 152°Csourcetypical |
| Glass transition | not sourced | 59.1°Csourcetypical |
| Max service temperature | 511°Csourcestrain point (ASTM C336) - stress-relaxation onset, not a rated service limit | 58.8°CsourceHDT 0.455 MPa (printed specimens) |
| Values for | Annealed soda-lime-silica float glass, Pilkington North America Technical Bulletin ATS-129 (04/2025) | Ultimaker PLA, 3D-printed specimens, XY (flat) orientation; 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 dated April 20, 2022. |
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 PLA is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Glass stronger than Plastic PLA?
Plastic PLA is stronger: its yield strength is 52.5 MPa against tensile strength 41 MPa for Glass (28%).
Which is lighter, Glass or Plastic PLA?
Plastic PLA is lighter: 1,240 kg/m³ against 2,500 kg/m³ for Glass.
Which is stiffer, Glass or Plastic PLA?
Glass is stiffer: Young's modulus 72 GPa against 3.25 GPa for Plastic PLA, so the same part in Glass deflects less under the same load.
Which is lighter for the same job, Glass or Plastic PLA?
For the same stiffness or strength: Glass is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic PLA is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Glass | Plastic PLA |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 11x heavier |
| Stiff beam (bending) | lighter | 2.33x heavier |
| Stiff panel or plate | lighter | 39% heavier |
| Strong rod or tie | 2.58x heavier | lighter |
| Strong beam | 2.38x heavier | lighter |
| Strong panel or plate | 2.28x heavier | lighter |
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, Glass or Plastic PLA?
Glass conducts heat better: 0.937 W/m·K against 0.13 W/m·K for Plastic PLA.