LE
ASTM D709 Grade LE
LE is a fine-weave cotton-fabric phenolic laminate to ASTM D709 Grade LE, the electrical counterpart of Grade L that adds improved dielectric strength while keeping the fine weave needed for detailed parts.
Reference datasheet — LE 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.
LE grades and fills
LE is supplied in 2 conditions, soft to hard.
Compare all 2 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
MoS2/graphite-filled bearing-grade cotton phenolic | Choose for water-lubricated bearings, wear pads and low-friction bushings; electrical properties are degraded. | 75 | 1.2 | 100 HRM | |
Flame-retardant modified LE-type cotton phenolic | Choose when a UL 94 V-0/V-1 rating is required in enclosures or switchgear; slightly lower impact strength. | 85 | 1.4 | 105 HRM |
Supply forms, finishes and certifications
Ways LE is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
ROD | Rolled/molded cotton phenolic rod, LE quality | Supply form |
SHEETDefault | Flat laminated sheet/plate | Supply form |
TUBE | Rolled cotton phenolic tube, LE quality | Supply form |
What is LE?
LE is a fine-weave cotton-fabric phenolic laminate to ASTM D709 Grade LE, the electrical counterpart of Grade L that adds improved dielectric strength while keeping the fine weave needed for detailed parts. It is the freest-machining member of the cotton-phenolic group at a machinability score of 88 and about 95 MPa tensile strength, and is stocked as sheet, rod and tube plus flame-retardant and MoS2-filled conditions. As a thermoset it cannot be welded or reshaped, and machined edges wick moisture, so they must be sealed and the part baked dry before high-voltage service. Grade L is the alternative when insulation is secondary. LE has a density of 1.36 g/cm³ (0.0491 lb/in³), lighter than 70% of composite grades. Its glass-transition temperature is 155°C (311 °F). LE has a tensile strength of 95 MPa (13.8 ksi), weaker than 69% of composite grades. Elongation at break is 1.5% and the elastic modulus is 7.5 GPa (1.09 Msi).
What is LE used for?
- precision insulating bushings
- electrical mounting components
- terminal insulators
Advantages
- Easy to machine — 88/100, better than 93% of composite grades
- Polishes to a fine finish — 55/100, better than 83% of composite grades
- Low embodied carbon — 4.5 kg CO₂/kg, better than 79% of composite grades
Limitations
- Absorbs moisture — dry before molding — 1.5%, worse than 81% of composite grades
- Needs corrosion protection — 60/100, worse than 79% of composite grades
- Limited service temperature — 120°C (248 °F), worse than 78% of composite grades
LE properties
Typical room-temperature values; bars are the position among composite grades.
Physical4
LE has a density of 1.36 g/cm³ (0.0491 lb/in³), lighter than 70% of composite grades. Its glass-transition temperature is 155°C (311 °F).
Mechanical12
LE has a tensile strength of 95 MPa (13.8 ksi), weaker than 69% of composite grades. Elongation at break is 1.5% and the elastic modulus is 7.5 GPa (1.09 Msi).
Thermal9
LE is rated for continuous service to 120°C (248 °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 25 µm/m·K (13.9 µin/in·°F).
Electrical7
LE 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 good (60/100), worse than 79% of composite grades. UV resistance is fair.
Sustainability4
Producing a kilogram of LE 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
LE's machinability is excellent (88/100, better than 93% 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. LE is highlighted; hover a dot for its name, or open the interactive family chart.
Working with LE
Is LE easy to machine?
Machines like hard wood/brass with carbide tooling — sharp positive rake, high speed, dust extraction (abrasive, respirable phenolic/cellulose dust); drill with slow feed to avoid delamination and exit chipping.
Can LE be welded?
Not weldable — a thermoset; join by bonding (epoxy/phenolic adhesive after abrading) or mechanical fasteners with washers to avoid crushing.
Can LE be formed, bent or molded?
Supplied as press-cured sheet/rod/tube; cannot be reformed. Thin sheet (<1.5 mm) can be cold-punched or hot-punched at 90–120 °C; blank dies must be sharp to prevent cracking.
LE 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 |
|---|---|---|
| cotton fabric (fine weave, cellulose)fine-weave cloth, typically <4 oz/yd² substrate | 42 – 55 | 50 |
| residual moisture/volatiles | 0.5 – 2.5 | 2 |
| phenol-formaldehyde (resole/novolac) rescured thermoset matrix | ≥ 42 (balance) |
What surface finishes work on LE?
Sand and buff for a smooth matt surface; seal machined edges with varnish or epoxy to limit moisture pickup; can be painted, but bare surfaces darken under UV. Bake dry before high-voltage testing.
Equivalent designations
Standards and trade names that resolve to LE in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D709 Grade LE
How much does LE cost?
LE is a premium-cost composite ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
LE — frequently asked
What is LE used for?
LE is typically used for precision insulating bushings, electrical mounting components and terminal insulators. In short: best-machining cotton phenolic; electrical version of Grade L; fine weave for detail parts.
What is the tensile strength of LE?
LE has a typical tensile strength of 95 MPa (13.8 ksi) — weaker than 69% of composite grades. Strength varies by condition: see the 2 listed tempers.
Is LE easy to machine?
Yes — machinability is rated excellent (88/100, better than 93% of composite grades). Machines like hard wood/brass with carbide tooling — sharp positive rake, high speed, dust extraction (abrasive, respirable phenolic/cellulose dust); drill with slow feed to avoid delamination and exit chipping.
Can LE be welded?
Not weldable — a thermoset; join by bonding (epoxy/phenolic adhesive after abrading) or mechanical fasteners with washers to avoid crushing.
What surface finishes work on LE?
Sand and buff for a smooth matt surface; seal machined edges with varnish or epoxy to limit moisture pickup; can be painted, but bare surfaces darken under UV. Bake dry before high-voltage testing.
Can LE be formed, bent or molded?
Supplied as press-cured sheet/rod/tube; cannot be reformed. Thin sheet (<1.5 mm) can be cold-punched or hot-punched at 90–120 °C; blank dies must be sharp to prevent cracking.
What is the maximum service temperature of LE?
LE is rated for continuous use to about 120°C (248 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does LE cost?
LE is a premium-cost composite ($$$), 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)
- NEMA LI 1 — Industrial Laminated Thermosetting Products — NEMA (1998)
- ASTM D2517 / D2518 — Laminated Thermosetting Rods and Tubes — ASTM International (2020)
- Engineered Materials Handbook Vol. 2: Engineering Plastics (phenolic laminates) — ASM International (1988)
- Canvas/cotton phenolic laminate grade LE datasheets — industrial laminate producers (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.