HPFS 7980 vs JGS1
Glass · grade comparison
HPFS 7980 and JGS1 are both glass grades. HPFS 7980 is harder — 800 HV against 750 HV for JGS1 — which matters for wear surfaces and threads. JGS1 runs hotter in service (1,050°C vs 900°C continuous).
HPFS 7980Choose it when surface hardness matters.
JGS1Choose it when the part sees heat.
HPFS 7980 vs JGS1: 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
Flexural Strength
Fracture Toughness (K_IC)
Hardness, Vickers
Hardness, Knoop
Shear Strength
Same in both: Poisson's Ratio 0.17 · Tensile Strength (Ultimate) 50 MPa7.3 ksi · Elongation at Break 0% · Compressive Strength 1,100 MPa160 ksi · Hardness, Mohs 6
Physical
Density and transition temperatures.
Density
Same in both: Melting Point (Solidus) 1,713°C3,115 °F · Refractive Index 1.459 · Light Transmission 93% · Porosity 0%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 740 J/kg·K0.18 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 0.55 µm/m·K0.31 µin/in·°F · Min Service Temperature -200°C-328 °F
Electrical
Conductivity and insulation.
Dielectric Constant (1 MHz)
Same in both: Electrical Resistivity 1×10¹⁶ Ω·m3.94×10²³ µΩ·in · Dielectric Strength 30 kV/mm762 V/mil · Dissipation Factor (1 MHz) 1×10⁻⁴ · Volume Resistivity 1×10¹⁸ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 95 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Polishability
Sintering / Firing Temperature
Same in both: Machinability 12 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Stiffness (E / density)
Same in both: Specific Strength (UTS / density) 23 kN·m/kg · Thermal Diffusivity 0.8 mm²/s · Thermal Shock Resistance Index 2
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 | HPFS 7980 | JGS1 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
HPFS 7980 vs JGS1 — frequently asked
What is the difference between HPFS 7980 and JGS1?
HPFS 7980 and JGS1 are both glass grades. HPFS 7980 is harder — 800 HV against 750 HV for JGS1 — which matters for wear surfaces and threads. JGS1 runs hotter in service (1,050°C vs 900°C continuous).
Which is cheaper, HPFS 7980 or JGS1?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose HPFS 7980 over JGS1?
Pick HPFS 7980 when surface hardness matters. Pick JGS1 when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in HPFS 7980 and JGS1 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.