C-Glass
C-Glass is a soda-lime-borosilicate fibre formulated for chemical durability and supplied mainly as surfacing veil, staple and continuous filament rather than as a primary structural reinforcement.
Reference datasheet — C-Glass is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
C-Glass tempers and conditions
C-Glass is supplied in one standard condition, VEIL.
Supply forms, finishes and certifications
Ways C-Glass is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
STAPLE | Chopped strand / staple fibre | Supply form |
FILDefault | Continuous filament / roving | Printing process |
What is C-Glass?
C-Glass is a soda-lime-borosilicate fibre formulated for chemical durability and supplied mainly as surfacing veil, staple and continuous filament rather than as a primary structural reinforcement. It is used to build the resin-rich corrosion barrier on the inside of FRP tanks and pipe, with a corrosion resistance score of 85 against 62 for E-glass. Mechanically it is the weaker fibre — 3300 MPa tensile strength, 69 GPa modulus, 4.8 % elongation and a service ceiling near 480 °C — so the structural plies behind the veil remain E- or S-glass. C-Glass has a density of 2.52 g/cm³ (0.091 lb/in³), lighter than 68% of glass grades. It melts at 1,000°C (1,832 °F). C-Glass has a tensile strength of 3,300 MPa (479 ksi), stronger than 96% of glass grades. Elongation at break is 4.8% and the elastic modulus is 69 GPa (10 Msi).
What is C-Glass used for?
- Corrosion-resistant composite surfacing veils
- Battery separators
- Filtration media
Advantages
- Ductile — tolerates forming and impact — 4.8%, better than 91% of glass grades
C-Glass properties
Typical room-temperature values; bars are the position among glass grades.
Physical4
C-Glass has a density of 2.52 g/cm³ (0.091 lb/in³), lighter than 68% of glass grades. It melts at 1,000°C (1,832 °F).
Mechanical12
C-Glass has a tensile strength of 3,300 MPa (479 ksi), stronger than 96% of glass grades. Elongation at break is 4.8% and the elastic modulus is 69 GPa (10 Msi).
Thermal5
C-Glass is rated for continuous service to 480°C (896 °F). It conducts heat at 1.1 W/m·K (0.607 BTU/hr·ft·°F), worse than 73% of glass grades. Thermal expansion is 6.3 µm/m·K (3.5 µin/in·°F).
Electrical5
C-Glass is an electrical insulator with a dielectric strength of 12 kV/mm (304.8 V/mil) and a resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (85/100), better than 65% of glass grades.
Sustainability4
Producing a kilogram of C-Glass takes about 45 MJ of energy and emits 2.4 kg of CO₂ — less than 58% of glass grades. Typical recycled content is 5%.
Manufacturability1
C-Glass's machinability is not recommended (12/100, worse than 68% of glass grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the glass family
Yield strength against density for every glass grade FabDigit runs. C-Glass is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C-Glass
Is C-Glass easy to machine?
Cured laminates containing C-glass are highly abrasive — use diamond or PCD-tipped tooling, high speed/low feed, and dust extraction.
Can C-Glass be welded?
Not weldable; glass fibre is joined only through the resin matrix (bonding, secondary lamination) or by mechanical fastening.
Can C-Glass be formed, bent or molded?
Supplied as veil, mat, chopped strand or roving; wet out easily with polyester, vinyl ester and epoxy in hand lay-up, filament winding and pultrusion.
C-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 |
|---|---|---|
| SiO2network former | 60 – 68 | 65 |
| Al2O3 | 2 – 6 | 4 |
| B2O3lowers melt viscosity, aids acid durability | 3 – 7 | 5 |
| CaO | 9 – 15 | 14 |
| MgO | 1 – 4 | 3 |
| Na2O + K2Ohigh alkali vs E-glass; lowers electrical resistivity | 8 – 11 | 8.5 |
| Fe2O3impurity | 0 – 0.5 | 0.2 |
| TiO2 + others | 0 – 0.5 | 0.3 |
What surface finishes work on C-Glass?
Veil gives the smooth resin-rich corrosion barrier surface directly; gel coat or a topcoat resin flood coat completes the finish — no plating or anodizing applies.
How much does C-Glass cost?
C-Glass is a standard-cost glass ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C-Glass — frequently asked
What is C-Glass used for?
C-Glass is typically used for corrosion-resistant composite surfacing veils, battery separators and filtration media. In short: chemically durable glass fibre; standard corrosion-barrier veil; non-structural surfacing ply.
What is the tensile strength of C-Glass?
C-Glass has a typical tensile strength of 3,300 MPa (479 ksi) — stronger than 96% of glass grades.
Is C-Glass easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 68% of glass grades). Cured laminates containing C-glass are highly abrasive — use diamond or PCD-tipped tooling, high speed/low feed, and dust extraction.
Can C-Glass be welded?
Not weldable; glass fibre is joined only through the resin matrix (bonding, secondary lamination) or by mechanical fastening.
What surface finishes work on C-Glass?
Veil gives the smooth resin-rich corrosion barrier surface directly; gel coat or a topcoat resin flood coat completes the finish — no plating or anodizing applies.
Can C-Glass be formed, bent or molded?
Supplied as veil, mat, chopped strand or roving; wet out easily with polyester, vinyl ester and epoxy in hand lay-up, filament winding and pultrusion.
What is the maximum service temperature of C-Glass?
C-Glass is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does C-Glass cost?
C-Glass is a standard-cost glass ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Engineered Materials Handbook Vol.1: Composites — Glass Fibers — ASM International (1987)
- ASM Handbook Vol.21: Composites — ASM International (2001)
- ASTM C581 — Chemical Resistance of Thermosetting Resins Used in Glass-Fiber-Reinforced Structures — ASTM International (2020)
- ASTM D578 — Standard Specification for Glass Fiber Strands — ASTM International (2018)
- C-glass surfacing veil technical data — Owens Corning / Johns Manville (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.