Borofloat 33 vs Pyrex 7740
Glass · grade comparison
Borofloat 33 and Pyrex 7740 are both glass grades. Borofloat 33 runs hotter in service (450°C vs 230°C continuous). On the shop floor, Borofloat 33 sits in a lower cost tier (standard, $$) than Pyrex 7740 (premium, $$$).
Borofloat 33Choose it when the part sees heat, or when cost is the deciding factor.
Borofloat 33 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Flexural Strength
Shear Strength
Fracture Toughness (K_IC)
Hardness, Knoop
Hardness, Mohs
Same in both: Elastic (Young's) Modulus 64 GPa9.3 Msi · Shear Modulus 26.7 GPa3.9 Msi · Bulk Modulus 36 GPa5.2 Msi · Poisson's Ratio 0.2 · Tensile Strength (Ultimate) 35 MPa5.1 ksi · Elongation at Break 0% · Compressive Strength 1,000 MPa145 ksi · Hardness, Vickers 480 HV
Physical
Density and transition temperatures.
Refractive Index
Same in both: Density 2.23 g/cm³0.08 lb/in³ · Light Transmission 92% · Porosity 0%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 830 J/kg·K0.2 BTU/lb·°F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Dielectric Strength
Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Dielectric Constant (1 MHz) 4.6 · Dissipation Factor (1 MHz) 0.0037 · Volume Resistivity 1×10¹⁵ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 92 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Polishability
Same in both: Machinability 12 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Embodied Water
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Typical Recycled Content 10%
Common Calculations
Ratios derived from the values above.
Same in both: Specific Strength (UTS / density) 16 kN·m/kg · Specific Stiffness (E / density) 28.7 MN·m/kg · 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 | Borofloat 33 | Pyrex 7740 |
|---|---|---|
| Default condition | Annealed Glass | — |
| Relative cost | $$ Standard | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Borofloat 33 vs Pyrex 7740 — frequently asked
What is the difference between Borofloat 33 and Pyrex 7740?
Borofloat 33 and Pyrex 7740 are both glass grades. Borofloat 33 runs hotter in service (450°C vs 230°C continuous). On the shop floor, Borofloat 33 sits in a lower cost tier (standard, $$) than Pyrex 7740 (premium, $$$).
Which is cheaper, Borofloat 33 or Pyrex 7740?
Borofloat 33 is the lower-cost material: it sits in the standard tier ($$) while Pyrex 7740 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose Borofloat 33 over Pyrex 7740?
Pick Borofloat 33 when the part sees heat, or when cost is the deciding factor.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Borofloat 33 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.