GPO-2
ASTM D709 Grade GPO-2
GPO-2 is the higher physical-strength member of the polyester glass-mat laminate family to ASTM D709, rated at 85 MPa tensile strength against 70 MPa for GPO-1, with a 140 °C maximum service temperature.
Reference datasheet — GPO-2 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.
GPO-2 grades and fills
GPO-2 is supplied in 3 conditions, soft to hard.
Compare all 3 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Hardened | Use for motor/transformer insulation and continuous duty above 155 °C where standard GPO-2 would embrittle. | 80 | 1.2 | 107 HRM | |
UL 94 V-0 / 5VA recognized flame-retardant build | Specify when a UL Yellow Card flame rating and RTI listing must be shown on the drawing. | 80 | 1 | 108 HRM | |
High physical strength / heavy-mat build | Pick when the part is structurally loaded (bus supports, cleats, arc barriers) and flexural/impact strength governs. | 105 | 1.4 | 110 HRM |
Supply forms, finishes and certifications
Ways GPO-2 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
COL | Pigmented sheet | Surface finish |
UV | Weather/UV-stabilized outdoor grade | Grade option |
STDDefault | Standard GPO-2 sheet | Standard supply |
What is GPO-2?
GPO-2 is the higher physical-strength member of the polyester glass-mat laminate family to ASTM D709, rated at 85 MPa tensile strength against 70 MPa for GPO-1, with a 140 °C maximum service temperature. It is chosen where greater impact and flexural strength are needed at moderate cost, and is available as sheet, rod and tube in high-strength, V-0, UV-stabilised and coloured conditions. The higher glass and filler loading makes it the most abrasive GPO grade to machine (machinability score 38). For arc chutes and tracking-critical high-voltage parts, use GPO-3 instead. GPO-2 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 67% of composite grades. Its glass-transition temperature is 120°C (248 °F). GPO-2 has a tensile strength of 85 MPa (12.3 ksi), weaker than 75% of composite grades. The elastic modulus is 11 GPa (1.6 Msi).
What is GPO-2 used for?
- appliance insulation parts
- structural electrical boards
- junction box components
Advantages
- Low embodied carbon — 4.5 kg CO₂/kg, better than 79% of composite grades
Limitations
- Hard to polish — 20/100, worse than 90% of composite grades
GPO-2 properties
Typical room-temperature values; bars are the position among composite grades.
Physical4
GPO-2 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 67% of composite grades. Its glass-transition temperature is 120°C (248 °F).
Mechanical10
GPO-2 has a tensile strength of 85 MPa (12.3 ksi), weaker than 75% of composite grades. The elastic modulus is 11 GPa (1.6 Msi).
Thermal9
GPO-2 is rated for continuous service to 140°C (284 °F). It conducts heat at 0.3 W/m·K (0.173 BTU/hr·ft·°F), worse than 63% of composite grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical7
GPO-2 is an electrical insulator with a dielectric strength of 14 kV/mm (355.6 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 58% of composite grades. UV resistance is fair.
Sustainability4
Producing a kilogram of GPO-2 takes about 78 MJ of energy and emits 4.5 kg of CO₂ — less than 87% of composite grades. Typical recycled content is 0%.
Manufacturability2
GPO-2's machinability is fair (38/100, better than 54% of composite 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 composite family
Yield strength against density for every composite grade FabDigit runs. GPO-2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GPO-2
Is GPO-2 easy to machine?
Machine dry with carbide or PCD tooling, high speed / moderate feed, and dust extraction — glass content is highly abrasive and the dust is a respiratory irritant.
Can GPO-2 be welded?
Not weldable or heat-formable (cross-linked thermoset); join by bolting, riveting or epoxy/acrylic structural adhesive with abraded surfaces.
Can GPO-2 be formed, bent or molded?
Supplied as flat press-cured sheet, rod or tube; parts are produced by punching (thin gauges, warm), sawing, routing and CNC milling rather than forming.
GPO-2 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 |
|---|---|---|
| unsaturated polyester resinstyrene-crosslinked, often DCPD or isophthalic type | 25 – 35 | 30 |
| glass fiber (chopped strand mat / continE-glass reinforcement | 20 – 35 | 28 |
| flame retardant + additiveshalogenated or phosphorus FR, catalyst, pigment, mold release | 1 – 5 | 3 |
| mineral filler (CaCO3 / alumina trihydraATH also acts as flame retardant / smoke suppressant | ≥ 30 (balance) |
What surface finishes work on GPO-2?
Edges should be deburred and sealed with epoxy or polyurethane varnish to limit moisture ingress; can be painted or silk-screened after solvent wipe, plating is not applicable.
Equivalent designations
Standards and trade names that resolve to GPO-2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D709 Grade GPO-2
How much does GPO-2 cost?
GPO-2 is a premium-cost composite ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GPO-2 — frequently asked
What is GPO-2 used for?
GPO-2 is typically used for appliance insulation parts, structural electrical boards and junction box components. In short: strongest GPO grade; impact-resistant polyester laminate; moderate cost, higher flexural strength.
What is the tensile strength of GPO-2?
GPO-2 has a typical tensile strength of 85 MPa (12.3 ksi) — weaker than 75% of composite grades. Strength varies by condition: see the 3 listed tempers.
Is GPO-2 easy to machine?
Not especially — machinability is rated fair (38/100, better than 54% of composite grades). Machine dry with carbide or PCD tooling, high speed / moderate feed, and dust extraction — glass content is highly abrasive and the dust is a respiratory irritant.
Can GPO-2 be welded?
Not weldable or heat-formable (cross-linked thermoset); join by bolting, riveting or epoxy/acrylic structural adhesive with abraded surfaces.
What surface finishes work on GPO-2?
Edges should be deburred and sealed with epoxy or polyurethane varnish to limit moisture ingress; can be painted or silk-screened after solvent wipe, plating is not applicable.
Can GPO-2 be formed, bent or molded?
Supplied as flat press-cured sheet, rod or tube; parts are produced by punching (thin gauges, warm), sawing, routing and CNC milling rather than forming.
What is the maximum service temperature of GPO-2?
GPO-2 is rated for continuous use to about 140°C (284 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does GPO-2 cost?
GPO-2 is a premium-cost composite ($$$), cheaper than about 51% 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
- ASTM D709 – Standard Specification for Laminated Thermosetting Materials — ASTM International (2023)
- NEMA LI 1 – Industrial Laminated Thermosetting Products — NEMA (2020)
- Glass-mat polyester laminate (GPO-1/GPO-2/GPO-3) datasheets — Electrical laminate producers (2023)
- Engineered Materials Handbook: Composites — ASM International (1987)
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.