Lead Glass (IEC G-500) vs Pyrex 7740
Glass · grade comparison
Lead Glass (IEC G-500) and Pyrex 7740 are both glass grades. Lead Glass (IEC G-500) is the stronger of the two: tensile strength 45 MPa (6.53 ksi) against 35 MPa (5.08 ksi) for Pyrex 7740, about 29% more. Pyrex 7740 is harder — 480 HV against 420 HV for Lead Glass (IEC G-500) — which matters for wear surfaces and threads. Pyrex 7740 is lighter (2.23 g/cm³ vs 3.1 g/cm³ for Lead Glass (IEC G-500)) and Lead Glass (IEC G-500) runs hotter in service (350°C vs 230°C continuous).
Lead Glass (IEC G-500)Choose it when strength drives the design, or when the part sees heat.
Pyrex 7740Choose it when surface hardness matters, or when weight is the constraint.
Lead Glass (IEC G-500) vs Pyrex 7740: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all glass grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all glass grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Lead Glass (IEC G-500)Pyrex 7740
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Compressive Strength
Flexural Strength
Fracture Toughness (K_IC)
Hardness, Vickers
Hardness, Knoop
Same in both: Elongation at Break 0% · Hardness, Mohs 5.5
Physical
Density and transition temperatures.
Density
Refractive Index
Light Transmission
Same in both: Porosity 0%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Same in both: Thermal Diffusivity 0.6 mm²/s · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every glass grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Lead Glass (IEC G-500) | Pyrex 7740 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Lead Glass (IEC G-500) vs Pyrex 7740 — frequently asked
Is Lead Glass (IEC G-500) stronger than Pyrex 7740?
Yes. Lead Glass (IEC G-500) has a typical tensile strength of 45 MPa (6.53 ksi) against 35 MPa (5.08 ksi) for Pyrex 7740 — about 29% more.
Which is cheaper, Lead Glass (IEC G-500) or Pyrex 7740?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose Lead Glass (IEC G-500) over Pyrex 7740?
Pick Lead Glass (IEC G-500) when strength drives the design, or when the part sees heat. Pick Pyrex 7740 when surface hardness matters, or when weight is the constraint.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Lead Glass (IEC G-500) and Pyrex 7740 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.