X
ASTM D709 Grade X
X is a general-purpose paper-base phenolic laminate to ASTM D709 Grade X, the economical entry point below the XX and XXX punching and electrical grades.
Reference datasheet — X 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.
Values for the X condition
X grades and fills
X is supplied in 4 conditions, soft to hard. X is the default FabDigit quotes; the values on this page are for it.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Cold-punchable paper phenolic | Choose the cold-punchable thin sheet (≤3 mm) for room-temperature piercing and blanking and as the base for single-sided FR-1/XPC copper-clad laminate; strength drops to 85 MPa and 110 °C. | 85 | 2.5 | 86 Shore D | |
Flame-retardant paper phenolic | Use the flame-retardant formulation when UL 94 V-0 approval is required for electrical enclosures, terminal boards and copper-clad base material; service temperature falls to 110 °C. | 85 | 1.5 | 88 Shore D | |
Hot-punchable / post-forming paper phenolic | Pick the more flexible resin system when parts are punched or bent hot at about 90–130 °C in high volume; formability costs strength, at 95 MPa instead of 110 MPa. | 95 | 2 | 87 Shore D | |
XDefault Standard paper/phenolic mechanical grade sheet | Use the general-purpose paper/phenolic mechanical sheet where moderate strength of 110 MPa, easy machining and low cost matter for low-voltage insulation and structural parts. | 110 | 1.5 | 88 Shore D |
Supply forms, finishes and certifications
Ways X is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CCL | Copper-clad XPC | Coating |
What is X?
X is a general-purpose paper-base phenolic laminate to ASTM D709 Grade X, the economical entry point below the XX and XXX punching and electrical grades. It provides moderate mechanical and electrical properties — about 110 MPa tensile strength with service to roughly 120 °C — for flat insulating board that is simply cut and drilled to size; related conditions cover punchable XP and XPC, flame-retardant and copper-clad material. Machinability is only fair at a score of 65 and the paper core absorbs moisture, so edges need sealing. Step up to XX or XXP where clean punching and higher dielectric strength matter. X has a density of 1.35 g/cm³ (0.0488 lb/in³), lighter than 75% of composite grades. Its glass-transition temperature is 150°C (302 °F). X has a tensile strength of 110 MPa (16 ksi), weaker than 64% of composite grades. Elongation at break is 1.5% and the elastic modulus is 9 GPa (1.31 Msi).
What is X used for?
- general insulation boards
- low-cost mechanical spacers
- electrical panel backing
Advantages
- Low embodied carbon — 3.5 kg CO₂/kg, better than 93% of composite grades
- Lightweight — 1.35 g/cm³ (0.0488 lb/in³), better than 75% of composite grades
- Easy to machine — 65/100, better than 75% of composite grades
Limitations
- Needs corrosion protection — 50/100, worse than 92% of composite grades
- Absorbs moisture — dry before molding — 2%, worse than 88% of composite grades
- Low fracture toughness — 2 MPa·√m (1.82 ksi·√in), worse than 87% of composite grades
- Degrades in UV without stabilisers — 25/100, worse than 86% of composite grades
- Limited service temperature — 120°C (248 °F), worse than 78% of composite grades
X properties
Typical room-temperature values for X-X; bars are the position among composite grades.
Physical4
X has a density of 1.35 g/cm³ (0.0488 lb/in³), lighter than 75% of composite grades. Its glass-transition temperature is 150°C (302 °F).
Mechanical13
X has a tensile strength of 110 MPa (16 ksi), weaker than 64% of composite grades. Elongation at break is 1.5% and the elastic modulus is 9 GPa (1.31 Msi).
Thermal9
X is rated for continuous service to 120°C (248 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), worse than 76% of composite grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical7
X is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 92% of composite grades. UV resistance is poor.
Sustainability2
Producing a kilogram of X takes about 75 MJ of energy and emits 3.5 kg of CO₂ — less than 91% of composite grades.
Manufacturability2
X's machinability is good (65/100, better than 75% 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. X is highlighted; hover a dot for its name, or open the interactive family chart.
Working with X
Is X easy to machine?
Cut with carbide or PCD tooling at high speed and light feed; the dust is abrasive and irritates the airway, so extraction is mandatory. Back up the exit side when drilling to prevent delamination.
Can X be welded?
Thermoset laminate — it cannot be welded or heat-fused; join with bolts, rivets or epoxy adhesive.
Can X be formed, bent or molded?
Standard Grade X is a cold-machined flat product only. Where blanking is required, specify XPC for room-temperature punching or XP for punching and post-forming after heating to 80–130 °C.
X 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 |
|---|---|---|
| phenol-formaldehyde resinresole/novolac phenolic binder | 35 – 50 | 42 |
| flame retardant / filleronly in FR variants | 0 – 10 | 0 |
| cellulose kraft paperreinforcement web | ≥ 50 (balance) |
What surface finishes work on X?
Sands, chamfers, silk-screens and accepts epoxy paint. It cannot be plated; seal the edges with varnish in warm, humid service to reduce water absorption.
Equivalent designations
Standards and trade names that resolve to X in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D709 Grade X
How much does X cost?
X is a standard-cost composite ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
X — frequently asked
What is X used for?
X is typically used for general insulation boards, low-cost mechanical spacers and electrical panel backing. In short: cheapest paper phenolic grade; general-purpose insulating board; base grade below XX.
What is the tensile strength of X?
X has a typical tensile strength of 110 MPa (16 ksi) — weaker than 64% of composite grades. Strength varies by condition: see the 4 listed tempers.
Is X easy to machine?
Reasonably — machinability is rated good (65/100, better than 75% of composite grades). Cut with carbide or PCD tooling at high speed and light feed; the dust is abrasive and irritates the airway, so extraction is mandatory. Back up the exit side when drilling to prevent delamination.
Can X be welded?
Thermoset laminate — it cannot be welded or heat-fused; join with bolts, rivets or epoxy adhesive.
What surface finishes work on X?
Sands, chamfers, silk-screens and accepts epoxy paint. It cannot be plated; seal the edges with varnish in warm, humid service to reduce water absorption.
Can X be formed, bent or molded?
Standard Grade X is a cold-machined flat product only. Where blanking is required, specify XPC for room-temperature punching or XP for punching and post-forming after heating to 80–130 °C.
What is the maximum service temperature of X?
X is rated for continuous use to about 120°C (248 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does X cost?
X is a standard-cost composite ($$), 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
- ASTM D709 Standard Specification for Laminated Thermosetting Materials — ASTM International (2017)
- NEMA LI 1 Industrial Laminated Thermosetting Products — NEMA (1998)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- Phenolic paper laminate (X/XP/XPC) technical data — Norplex-Micarta / Professional Plastics (2023)
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.