GPO-1
ASTM D709 Grade GPO-1
GPO-1 is a general-purpose polyester glass-mat laminate to ASTM D709 Grade GPO-1, supplied as press-cured flat sheet, rod and punching stock.
Reference datasheet — GPO-1 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-1 grades and fills
GPO-1 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 |
|---|---|---|---|---|---|
hot/cold punching grade (thin sheet, 0.8–3 mm) | Use the thin sheet (≤3 mm) with adjusted resin/filler ratio when parts are punched cold or warm in high volume, such as insulating gaskets, instead of being machined from plate. | 60 | 1.7 | 100 HRM | |
GPO-1UL94 V-0 | Choose the ATH-, halogen- or phosphorus-modified board when UL 94 V-0 is mandatory for insulation inside electrical cabinets; tensile strength falls to 65 MPa versus the standard sheet. | 65 | 1.4 | 105 HRM | |
H 180 °C GPO-1 | Pick the heat-resistant polyester/vinyl ester system when continuous service must reach Class H at 180 °C, as in motor and dry-type transformer insulation. | 68 | 1.3 | 108 HRM |
Supply forms, finishes and certifications
Ways GPO-1 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
STDDefault | GPO-1 / | Standard supply |
What is GPO-1?
GPO-1 is a general-purpose polyester glass-mat laminate to ASTM D709 Grade GPO-1, supplied as press-cured flat sheet, rod and punching stock. It provides economical mechanical and electrical insulation at 70 MPa tensile strength and a 155 °C maximum service temperature, with flame-retardant, high-temperature and punching conditions available. It does not offer the arc- and track-resistance of GPO-3, so it is not suited to arc-facing switchgear parts. As a thermoset it cannot be welded or post-formed, and machining is abrasive. GPO-1 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-1 has a tensile strength of 70 MPa (10.2 ksi), weaker than 81% of composite grades. The elastic modulus is 10 GPa (1.45 Msi).
What is GPO-1 used for?
- general electrical insulation
- low-voltage terminal boards
- junction box liners
Advantages
- Low embodied carbon — 4.2 kg CO₂/kg, better than 88% of composite grades
Limitations
- Hard to polish — 25/100, worse than 76% of composite grades
GPO-1 properties
Typical room-temperature values; bars are the position among composite grades.
Physical4
GPO-1 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-1 has a tensile strength of 70 MPa (10.2 ksi), weaker than 81% of composite grades. The elastic modulus is 10 GPa (1.45 Msi).
Thermal9
GPO-1 is rated for continuous service to 155°C (311 °F). It conducts heat at 0.32 W/m·K (0.185 BTU/hr·ft·°F), worse than 55% of composite grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical7
GPO-1 is an electrical insulator with a dielectric strength of 14 kV/mm (355.6 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 52% of composite grades. UV resistance is fair.
Sustainability4
Producing a kilogram of GPO-1 takes about 70 MJ of energy and emits 4.2 kg of CO₂ — less than 93% of composite grades. Typical recycled content is 0%.
Manufacturability2
GPO-1's machinability is fair (45/100, better than 63% 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-1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with GPO-1
Is GPO-1 easy to machine?
Saws, mills, drills and turns without difficulty, but the glass and inorganic filler are strongly abrasive: use carbide or PCD tooling at high speed and low feed. Run dust extraction, as the dust is an irritant.
Can GPO-1 be welded?
Thermoset — not weldable. Join with epoxy or acrylic structural adhesive, or mechanically with bolts and rivets.
Can GPO-1 be formed, bent or molded?
Sheet is fully cured and cannot be reheated and formed; thin gauges punch cleanly. Finished thickness and shape are set during lamination, then trimmed by machining.
GPO-1 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 resinThermoset matrix with styrene crosslinking | 20 – 35 | 28 |
| E-glass fiber (chopped strand mat)chopped strand glass mat reinforcement | 20 – 35 | 28 |
| pigment / release agent / catalystcolorant and curing additives | 0 – 3 | 2 |
| mineral filler (CaCO3 / ATH / clay)Inorganic filler; affects electrical and flame-retardant behavior | ≥ 30 (balance) |
What surface finishes work on GPO-1?
Chamfer and seal edges with epoxy or varnish to limit moisture pick-up and surface tracking. Silk-screen marking is practical; plating and polishing are not.
Equivalent designations
Standards and trade names that resolve to GPO-1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D709 Grade GPO-1
How much does GPO-1 cost?
GPO-1 is a premium-cost composite ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
GPO-1 — frequently asked
What is GPO-1 used for?
GPO-1 is typically used for general electrical insulation, low-voltage terminal boards and junction box liners. In short: lowest-cost GPO grade; economical insulating board; no arc-track rating.
What is the tensile strength of GPO-1?
GPO-1 has a typical tensile strength of 70 MPa (10.2 ksi) — weaker than 81% of composite grades. Strength varies by condition: see the 3 listed tempers.
Is GPO-1 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 63% of composite grades). Saws, mills, drills and turns without difficulty, but the glass and inorganic filler are strongly abrasive: use carbide or PCD tooling at high speed and low feed. Run dust extraction, as the dust is an irritant.
Can GPO-1 be welded?
Thermoset — not weldable. Join with epoxy or acrylic structural adhesive, or mechanically with bolts and rivets.
What surface finishes work on GPO-1?
Chamfer and seal edges with epoxy or varnish to limit moisture pick-up and surface tracking. Silk-screen marking is practical; plating and polishing are not.
Can GPO-1 be formed, bent or molded?
Sheet is fully cured and cannot be reheated and formed; thin gauges punch cleanly. Finished thickness and shape are set during lamination, then trimmed by machining.
What is the maximum service temperature of GPO-1?
GPO-1 is rated for continuous use to about 155°C (311 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does GPO-1 cost?
GPO-1 is a premium-cost composite ($$$), 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 (2017)
- IEC 60893 / IEC 60112 (CTI) Insulating materials — industrial rigid laminated sheets — IEC (2020)
- GPO-1 / GPO-3 polyester glass laminate technical data — Glastic/Norplex-Micarta (2023)
- Handbook of Composites / Engineering Plastics — thermoset laminates — ASM International (2000)
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.