Cork Composite Core NL25
Grade
also Corecork
NL25 = high-density cork core
Choose where higher core shear/compression is needed, e.g. hardpoints, decks and fastener zones.
Values for the NL25 condition
Other Cork Composite Core grades and fills
Cork Composite Core is listed in 5 conditions; see the grade overview at Cork Composite Core.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Low-density cork core | Lightest grade for weight-critical, lightly loaded sandwich skins and damping layers. | — | 0.45 | 12 | 25 Shore A |
Fire-retardant treated core for rail/marine interiors | Binder/additive package tuned for EN 45545-2 HL2–HL3 and IMO low smoke/toxicity interior panels. | — | 0.75 | 9 | 38 Shore A |
NL20Default Standard-density cork core | General-purpose marine/rail sandwich core balancing damping, strength and resin uptake. | — | 0.8 | — | — |
NL25This page High-density cork core | Choose where higher core shear/compression is needed, e.g. hardpoints, decks and fastener zones. | — | 1 | 9 | 45 Shore A |
Cold rolled | Denser rubber-bonded cork for gaskets, anti-vibration pads and machinery mounts rather than lightweight sandwich cores. | — | 2 | 18 | 22 Shore D |
What is Cork Composite Core NL25?
Cork Composite Core NL25 is Cork Composite Core in the NL25 grade — choose where higher core shear/compression is needed, e.g. hardpoints, decks and fastener zones. Cork Composite Core NL25 has a tensile strength of 1 MPa (0.16 ksi), weaker than 95% of composite grades. Elongation at break is 9% and the elastic modulus is 0.03 GPa (0.0044 Msi). Cork Composite Core NL25 has a density of 0.23 g/cm³ (0.0083 lb/in³), lighter than 83% of composite grades. NL20 is the default condition FabDigit quotes; NL25 is available on request or by drawing note.
Advantages
- Low embodied carbon — 0.5 kg CO₂/kg, better than 100% of composite grades
- Easy to machine — 88/100, better than 93% of composite grades
- Ductile — tolerates forming and impact — 9%, better than 92% of composite grades
- Lightweight — 0.23 g/cm³ (0.0083 lb/in³), better than 83% of composite grades
Limitations
- Absorbs moisture — dry before molding — 6%, worse than 97% of composite grades
- Low stiffness — 0.03 GPa (0.0044 Msi), worse than 96% of composite grades
- Poor heat conductor — 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 83% of composite grades
- Limited service temperature — 120°C (248 °F), worse than 78% of composite grades
Cork Composite Core NL25 properties
Typical room-temperature values for Cork Composite Core NL25; 19 are specific to this condition. Other listed values are Cork Composite Core reference data and may not represent this condition. Bars are the position among composite grades.
Physical3
Cork Composite Core NL25 has a density of 0.23 g/cm³ (0.0083 lb/in³), lighter than 83% of composite grades.
Mechanical9
Cork Composite Core NL25 has a tensile strength of 1 MPa (0.16 ksi), weaker than 95% of composite grades. Elongation at break is 9% and the elastic modulus is 0.03 GPa (0.0044 Msi).
Thermal8
Cork Composite Core NL25 is rated for continuous service to 120°C (248 °F). It conducts heat at 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 83% of composite grades. Thermal expansion is 50 µm/m·K (27.8 µin/in·°F).
Chemical & Environmental2
UV resistance is fair.
Sustainability3
Producing a kilogram of Cork Composite Core NL25 takes about 6 MJ of energy and emits 0.5 kg of CO₂ — less than 100% of composite grades. Typical recycled content is 90%.
Manufacturability1
Cork Composite Core NL25's machinability is excellent (88/100, better than 93% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Cork Composite Core NL25
Is Cork Composite Core easy to machine?
Cuts easily with sharp knives, band saw, router or CNC; use vacuum extraction for dust and avoid crushing edges with dull tools.
Can Cork Composite Core be welded?
Not weldable — panels are joined by adhesive bonding, scarf joints or resin fillets between core blocks.
Can Cork Composite Core be formed, bent or molded?
Flexible enough to conform to single- and mild double-curvature molds cold; hot-forming above ~90 °C improves drape, and perforated/grooved sheets are used for vacuum infusion.
What surface finishes work on Cork Composite Core?
Skins bond directly with epoxy, vinylester or polyester; seal or prime exposed faces since untreated cork absorbs resin/moisture and darkens under UV.
Cork Composite Core 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 |
|---|---|---|
| cork granulate (Quercus suber)expanded/agglomerated granules, by-product of cork stopper production | 82 – 95 | 90 |
| polyurethane binderMDI-based PU; rubber (NBR/SBR) binder in cork–rubber grades | 5 – 18 | 10 |
Cork Composite Core NL25 — frequently asked
What is Cork Composite Core NL25 used for?
Cork Composite Core NL25 is typically used for boat deck cores, acoustic/vibration-damping panels and rail interior panels. In short: best-damping natural core; drapes cold to curvature; low stiffness versus foam cores.
What is the tensile strength of Cork Composite Core NL25?
Cork Composite Core NL25 has a typical tensile strength of 1 MPa (0.16 ksi) — weaker than 95% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is Cork Composite Core NL25 easy to machine?
Yes — machinability is rated excellent (88/100, better than 93% of composite grades). Cuts easily with sharp knives, band saw, router or CNC; use vacuum extraction for dust and avoid crushing edges with dull tools.
Can Cork Composite Core NL25 be welded?
Not weldable — panels are joined by adhesive bonding, scarf joints or resin fillets between core blocks.
What surface finishes work on Cork Composite Core NL25?
Skins bond directly with epoxy, vinylester or polyester; seal or prime exposed faces since untreated cork absorbs resin/moisture and darkens under UV.
Can Cork Composite Core NL25 be formed, bent or molded?
Flexible enough to conform to single- and mild double-curvature molds cold; hot-forming above ~90 °C improves drape, and perforated/grooved sheets are used for vacuum infusion.
What is the maximum service temperature of Cork Composite Core NL25?
Cork Composite Core NL25 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.
Sources
- CoreCork NL series technical datasheet — Amorim Cork Composites (2023)
- ASTM C273 Shear Properties of Sandwich Core Materials — ASTM (2020)
- ASTM D1621 Compressive Properties of Rigid Cellular Plastics — ASTM (2016)
- EN 45545-2 Railway applications — Fire behaviour of materials — CEN (2020)
- Cellular Solids: Structure and Properties (cork chapter) — Cambridge University Press (1997)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.