S-Glass R (R-Glass)
Grade
European/3B HiPer-tex style high-strength fibre; slightly lower strength than S-2 but cheaper and widely available for wind and pressure-vessel parts.
Values for the R condition
Other S-Glass tempers and conditions
S-Glass is listed in 3 conditions; see the grade overview at S-Glass.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Chinese domestic high-strength glass fibre | Cost-driven domestic substitute for S-glass in pressure vessels, sporting goods and armour backing; property scatter is wider than AGY S-2. | — | 4,300 | 5.2 | 630 HV | 1 W/m·K |
RThis page R-Glass | European/3B HiPer-tex style high-strength fibre; slightly lower strength than S-2 but cheaper and widely available for wind and pressure-vessel parts. | — | 4,400 | 4.8 | 650 HV | 1 W/m·K |
S-2Default S-2 Glass | Default commercial high-strength grade for filament winding, ballistic laminates and aerospace prepreg. | — | 4,890 | 5.7 | 640 HV | 1 W/m·K |
What is S-Glass R?
S-Glass R is S-Glass in the R grade — european/3B HiPer-tex style high-strength fibre; slightly lower strength than S-2 but cheaper and widely available for wind and pressure-vessel parts. S-Glass R has a tensile strength of 4,400 MPa (638 ksi), stronger than 100% of glass grades. Elongation at break is 4.8% and the elastic modulus is 86 GPa (12.5 Msi). S-Glass R has a density of 2.54 g/cm³ (0.0918 lb/in³), lighter than 64% of glass grades. It melts at 1,500°C (2,732 °F). S-2 is the default condition FabDigit quotes; R is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 4.8%, better than 91% of glass grades
Limitations
- Hard to polish — 45/100, worse than 92% of glass grades
S-Glass R properties
Typical room-temperature values for S-Glass R; 13 are specific to this condition. Other listed values are S-Glass reference data and may not represent this condition. Bars are the position among glass grades.
Physical4
S-Glass R has a density of 2.54 g/cm³ (0.0918 lb/in³), lighter than 64% of glass grades. It melts at 1,500°C (2,732 °F).
Mechanical11
S-Glass R has a tensile strength of 4,400 MPa (638 ksi), stronger than 100% of glass grades. Elongation at break is 4.8% and the elastic modulus is 86 GPa (12.5 Msi).
Thermal5
S-Glass R is rated for continuous service to 600°C (1,112 °F). It conducts heat at 1.4 W/m·K (0.809 BTU/hr·ft·°F), better than 58% of glass grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical4
S-Glass R has an electrical resistivity of 1×10¹³ Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (75/100), better than 51% of glass grades.
Sustainability4
Producing a kilogram of S-Glass R takes about 75 MJ of energy and emits 4.2 kg of CO₂ — more than 63% of glass grades. Typical recycled content is 0%.
Manufacturability2
S-Glass R's machinability is not recommended (12/100, worse than 68% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S-Glass R
Is S-Glass easy to machine?
Cured S-glass laminates are highly abrasive — use PCD or diamond-coated routers/drills, high speed with low feed, and dust extraction; dry cutting glazes the tool quickly.
Can S-Glass be welded?
Not weldable; join composites by adhesive bonding or co-curing, mechanical fastening with oversize bearing plies.
Can S-Glass be formed, bent or molded?
Supplied as roving, fabric or prepreg; processed by filament winding, pultrusion, RTM or autoclave cure at 120–180 °C — silane sizing must match the resin (epoxy, phenolic, PA).
What surface finishes work on S-Glass?
Edge-seal with resin or gelcoat to stop moisture wicking along fibres; peel-ply or light abrasion before bonding, no plating or anodizing applicable.
S-Glass chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| SiO2glass former | 64 – 66 | 65 |
| Al2O3raises modulus and strength | 24 – 25.5 | 25 |
| MgOnetwork modifier | 9.5 – 10.5 | 10 |
| Na2O+K2Oalkali kept low for durability | 0 – 0.3 | 0.1 |
| Fe2O3impurity | 0 – 0.2 | 0.05 |
| B2O3essentially boron-free | 0 – 0.1 | 0 |
S-Glass R — frequently asked
What is S-Glass R used for?
S-Glass R is typically used for aerospace composites, ballistic armor, pressure vessels and sporting goods. In short: strongest common glass fibre; higher modulus than E-glass; aerospace and ballistic grade.
What is the tensile strength of S-Glass R?
S-Glass R has a typical tensile strength of 4,400 MPa (638 ksi) — stronger than 100% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is S-Glass R easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 68% of glass grades). Cured S-glass laminates are highly abrasive — use PCD or diamond-coated routers/drills, high speed with low feed, and dust extraction; dry cutting glazes the tool quickly.
Can S-Glass R be welded?
Not weldable; join composites by adhesive bonding or co-curing, mechanical fastening with oversize bearing plies.
What surface finishes work on S-Glass R?
Edge-seal with resin or gelcoat to stop moisture wicking along fibres; peel-ply or light abrasion before bonding, no plating or anodizing applicable.
Can S-Glass R be formed, bent or molded?
Supplied as roving, fabric or prepreg; processed by filament winding, pultrusion, RTM or autoclave cure at 120–180 °C — silane sizing must match the resin (epoxy, phenolic, PA).
What is the maximum service temperature of S-Glass R?
S-Glass R is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- S-2 Glass Fiber Product Information — AGY (2020)
- ASM Handbook Vol. 21: Composites — Glass Fibers — ASM International (2001)
- Engineered Materials Handbook Vol. 1: Composites — ASM International (1987)
- HiPer-tex W2020 High Performance Glass Rovings — 3B Fibreglass (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.