Glass vs. Plastic TPU

Compare Glass vs. Plastic TPU strength, stiffness, weight and thermal properties.

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Mechanical
Try it on a partA sample part to run stress or thermal on, free in your browser	Open in LessCAD	Open in LessCAD
Yield strength	not given (tensile used)	not given (tensile used)
Ultimate tensile strength	41MPasourcetypical mean surface tensile stress at fracture (MOR), 60 s load, weathered, 50% breakage probability	23.7MPasourcetypical, stress at break
Flexural strength	41MPasourcemean MOR (same value as tensile)	4.1MPasourcetypical
Elongation at break	not sourced	not sourced
Young's modulus (stiffness)	72GPasourcetypical1,075x stiffer	0.067GPasourcetypical
Density	2,500kg/m³sourcetypical	1,220kg/m³sourcetypical2.05x lighter
Strength to weight	16.4kN·m/kg	19.4kN·m/kg18% higher
Stiffness to weight	28.8MN·m/kg524x higher	0.0549MN·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	234m/s
Thermal
Thermal conductivity	0.937W/m·Ksourcetypical at 75 F	not sourced
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	not sourced
Heats up and cools (diffusivity)	0.426mm²/s	not sourced
Thermal shock resistance	50.1W/m	not sourced
Melting point	not sourced	217°Csourcetypical
Max service temperature	511°Csourcestrain point (ASTM C336) - stress-relaxation onset, not a rated service limit	50.3°CsourceHDT 0.455 MPa (printed specimens)
Values for	Annealed soda-lime-silica float glass, Pilkington North America Technical Bulletin ATS-129 (04/2025)	Ultimaker TPU 95A, 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 (file v5.00), April 29, 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 TPU is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is Glass stronger than Plastic TPU?

Glass is stronger: its tensile strength is 41 MPa against 23.7 MPa for Plastic TPU (1.73x).

Which is lighter, Glass or Plastic TPU?

Plastic TPU is lighter: 1,220 kg/m³ against 2,500 kg/m³ for Glass.

Which is stiffer, Glass or Plastic TPU?

Glass is stiffer: Young's modulus 72 GPa against 0.067 GPa for Plastic TPU, so the same part in Glass deflects less under the same load.

Which is lighter for the same job, Glass or Plastic TPU?

For the same stiffness or strength: Glass is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic TPU is lighter for a strong rod or tie, strong beam, strong panel or plate.

Part that must be	Glass	Plastic TPU
Stiff rod or tie (tension)	lighter	524x heavier
Stiff beam (bending)	lighter	16x heavier
Stiff panel or plate	lighter	5x heavier
Strong rod or tie	18% heavier	lighter
Strong beam	42% heavier	lighter
Strong panel or plate	1.56x 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).

Among 72 materials

Stiffness against density

Strength against density