Borofloat 33 vs ULE 7972
Glass · grade comparison
Borofloat 33 and ULE 7972 are both glass grades. ULE 7972 is the stronger of the two: tensile strength 50 MPa (7.25 ksi) against 35 MPa (5.08 ksi) for Borofloat 33, about 43% more. ULE 7972 is harder — 550 HV against 480 HV for Borofloat 33 — which matters for wear surfaces and threads. ULE 7972 is stiffer (67.6 GPa vs 64 GPa) and ULE 7972 runs hotter in service (890°C vs 450°C continuous). On the shop floor, Borofloat 33 sits in a lower cost tier (standard, $$) than ULE 7972 (high, $$$$).
Borofloat 33Choose it when cost is the deciding factor.
ULE 7972Choose it when strength drives the design, or when surface hardness matters.
Borofloat 33 vs ULE 7972: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Flexural Strength
Shear Strength
Fracture Toughness (K_IC)
Hardness, Vickers
Hardness, Knoop
Same in both: Hardness, Mohs 6
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).
Same in both: Corrosion Resistance 92 / 100
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)
Thermal Diffusivity
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 | ULE 7972 |
|---|---|---|
| Default condition | Annealed Glass | — |
| Relative cost | $$ Standard | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Borofloat 33 vs ULE 7972 — frequently asked
Is ULE 7972 stronger than Borofloat 33?
Yes. ULE 7972 has a typical tensile strength of 50 MPa (7.25 ksi) against 35 MPa (5.08 ksi) for Borofloat 33 — about 43% more.
Which is cheaper, Borofloat 33 or ULE 7972?
Borofloat 33 is the lower-cost material: it sits in the standard tier ($$) while ULE 7972 is high ($$$$). 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 ULE 7972?
Pick Borofloat 33 when cost is the deciding factor. Pick ULE 7972 when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Borofloat 33 and ULE 7972 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.