FabDigit

PETG vs PBT and 2 more: properties

PETGPBTPETPLA

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

2.1 GPa0.3 Msi
2.6 GPa0.38 Msi
3.1 GPa0.45 Msi
3.4 GPa0.49 Msi

Shear Modulus

0.77 GPa0.11 Msi
0.93 GPa0.13 Msi
1.1 GPa0.16 Msi
1.3 GPa0.18 Msi

Poisson's Ratio

0.4
0.4
0.4
0.36

Tensile Strength (Ultimate)

50 MPa7.3 ksi
55 MPa8 ksi
82 MPa11.9 ksi
50 MPa7.3 ksi

Yield Strength (0.2% offset)

50 MPa7.3 ksi
55 MPa8 ksi
80 MPa11.6 ksi
48 MPa7 ksi

Elongation at Break

120%
100%
20%
5%

Compressive Strength

60 MPa8.7 ksi
85 MPa12.3 ksi
100 MPa14.5 ksi
70 MPa10.2 ksi

Flexural Strength

70 MPa10.2 ksi
88 MPa12.8 ksi
120 MPa17.4 ksi
83 MPa12 ksi

Flexural Modulus

2.1 GPa0.3 Msi
2.4 GPa0.35 Msi
3.1 GPa0.45 Msi
3.5 GPa0.51 Msi

Izod Impact, Notched

95 J/m1.8 ft·lbf/in
50 J/m0.94 ft·lbf/in
40 J/m0.75 ft·lbf/in
22 J/m0.41 ft·lbf/in

Hardness, Shore D

78 Shore D
82 Shore D
85 Shore D
83 Shore D

Hardness, Rockwell R

115 HRR
118 HRR
120 HRR
105 HRR

Bulk Modulus

4 GPa0.61 Msi
5 GPa0.65 Msi
4 GPa0.58 Msi

Compressive Modulus

2.4 GPa0.35 Msi
3 GPa0.44 Msi
3.2 GPa0.46 Msi

Shear Strength

45 MPa6.5 ksi
55 MPa8 ksi
45 MPa6.5 ksi

Fracture Toughness (K_IC)

2.5 MPa·√m2.3 ksi·√in
4 MPa·√m3.6 ksi·√in
2.2 MPa·√m2 ksi·√in

Hardness, Rockwell M

75 HRM
94 HRM

Physical

Density and transition temperatures.

Density

1.27 g/cm³0.05 lb/in³
1.31 g/cm³0.05 lb/in³
1.39 g/cm³0.05 lb/in³
1.24 g/cm³0.04 lb/in³

Glass Transition (Tg)

80°C176 °F
55°C131 °F
79°C174 °F
60°C140 °F

Water Absorption (24 h)

0.13%
0.09%
0.11%
0.3%

Water Absorption (Saturation)

0.5%
0.45%
0.5%
1%

Refractive Index

1.57
1.575
1.46

Light Transmission

89%
88%
88%

Melting Temperature (Tm)

225°C437 °F
255°C491 °F
160°C320 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.2 W/m·K0.12 BTU/hr·ft·°F
0.25 W/m·K0.14 BTU/hr·ft·°F
0.25 W/m·K0.14 BTU/hr·ft·°F
0.13 W/m·K0.08 BTU/hr·ft·°F

Specific Heat Capacity

1,200 J/kg·K0.29 BTU/lb·°F
1,500 J/kg·K0.36 BTU/lb·°F
1,150 J/kg·K0.27 BTU/lb·°F
1,800 J/kg·K0.43 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

68 µm/m·K37.8 µin/in·°F
80 µm/m·K44.4 µin/in·°F
65 µm/m·K36.1 µin/in·°F
70 µm/m·K38.9 µin/in·°F

Max Service Temperature (continuous)

63°C145 °F
110°C230 °F
100°C212 °F
50°C122 °F

Min Service Temperature

-40°C-40 °F
-40°C-40 °F
-20°C-4 °F
-20°C-4 °F

Heat Deflection Temp. @ 0.45 MPa

70°C158 °F
155°C311 °F
115°C239 °F
55°C131 °F

Heat Deflection Temp. @ 1.8 MPa

64°C147 °F
60°C140 °F
80°C176 °F
50°C122 °F

Vicat Softening Point (B50)

82°C180 °F
178°C352 °F
180°C356 °F
58°C136 °F

Limiting Oxygen Index

23%
21%
22%
20%

Max Service Temperature (short-term)

75°C167 °F
160°C320 °F
150°C302 °F
65°C149 °F

Electrical

Conductivity and insulation.

Dielectric Strength

16 kV/mm406 V/mil
23 kV/mm584 V/mil
22 kV/mm559 V/mil
19 kV/mm483 V/mil

Dielectric Constant (1 MHz)

2.8
3.1
3.2
3

Dissipation Factor (1 MHz)

0.02
0.02
0.018
0.013

Surface Resistivity

1×10¹⁶ Ω
1×10¹⁵ Ω
1×10¹⁵ Ω
1×10¹⁶ Ω

Comparative Tracking Index (CTI)

600 V
600 V

Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Volume Resistivity 1×10¹⁶ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
82 / 100
70 / 100
55 / 100

UV / Weathering Resistance

45 / 100
35 / 100
30 / 100
40 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

65 / 100
68 / 100
78 / 100
60 / 100

Weldability

80 / 100
70 / 100
45 / 100
70 / 100

Formability (cold)

88 / 100
20 / 100
50 / 100
25 / 100

Polishability

72 / 100
55 / 100
60 / 100
55 / 100

Mold Shrinkage

0.35%
1.8%
2%
0.4%

Processing Melt Temperature (typ.)

245°C473 °F
250°C482 °F
280°C536 °F
205°C401 °F

Mold Temperature (typ.)

25°C77 °F
70°C158 °F
135°C275 °F
55°C131 °F

Melt Flow Rate

25 g/10 min
6 g/10 min

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

84 MJ/kg36,114 BTU/lb
105 MJ/kg45,142 BTU/lb
82 MJ/kg35,254 BTU/lb
50 MJ/kg21,496 BTU/lb

Embodied Carbon (primary production)

3.2 kg CO₂/kg
5 kg CO₂/kg
2.8 kg CO₂/kg
1.8 kg CO₂/kg

Embodied Water

210 L/kg25.2 gal/lb
250 L/kg30 gal/lb
120 L/kg14.4 gal/lb
350 L/kg41.9 gal/lb

Typical Recycled Content

0%
5%
25%
2%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

39 kN·m/kg
42 kN·m/kg
59 kN·m/kg
40 kN·m/kg

Specific Stiffness (E / density)

1.7 MN·m/kg
2 MN·m/kg
2.2 MN·m/kg
2.7 MN·m/kg

Modulus of Resilience

595 kJ/m³
582 kJ/m³
1,032 kJ/m³
339 kJ/m³

Thermal Diffusivity

0.1 mm²/s
0.1 mm²/s
0.2 mm²/s
0.1 mm²/s

Same in both: Thermal Shock Resistance Index 0

Strength versus weight

Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scalePETGPBTPETPLA

Manufacturing and finishing

CapabilityPETGPBTPETPLA
CNC machiningYesYes
Sheet metalYesYes
Injection moldingYesYesYes
3D printingYesYes
Default conditionUnfilledUnfilledUnfilledStandard
Relative cost$ Budget$$ Standard$$ Standard$ Budget
Min. machined wall0.5 mm0.5 mm
Best machined surfaceRa 0.8 µmRa 0.8 µm
Chrome Plating (Plastic)YesYesYes
Conductive CoatingYesYes
Dyeing (Nylon)YesYes
PaintingYesYesYes
Primer CoatingYesYes
Spray PaintingYesYesYes
Tinted CoatingYesYes
Vacuum MetallizationYesYes
Waterproof CoatingYesYes

They share 3 finishes: EMI Shielding Coating, Soft Touch Coating, UV Coating.

Ready to make it?

Upload a CAD file and FabDigit prices the part in PETG and PBT side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.