Natural Cork
Natural Cork is the bark of the cork oak (Quercus suber), a closed-cell natural cellular material available as natural sheet and stopper stock (NAT), resin-bonded agglomerate (AGG), expanded insulation corkboard (ICB) and cork-rubber grades (CR).
Reference datasheet — Natural Cork 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.
Natural Cork tempers and conditions
Natural Cork is supplied in 3 conditions, soft to hard.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Expanded (black) insulation corkboard, steam-expanded, binder-free | Choose for thermal/acoustic insulation and cryogenic pipe supports — lowest conductivity, self-bonded by its own resins, no added binder. | 0.08 | 0.04 W/m·K | |||
Agglomerated (composition) cork, granules + resin binder | Choose for sheets, gasket stock, floor underlay and cork boards where large uniform panels and low cost matter more than pure elasticity. | 0.8 | 5 | 0.06 W/m·K | ||
Cold rolled | Choose for oil-resistant gaskets, transformer and machine-mount pads where higher strength, sealing and fluid resistance are needed. | 3 | 25 | 0.1 W/m·K |
Supply forms, finishes and certifications
Ways Natural Cork is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
NATDefault | Natural cork | Standard supply |
What is Natural Cork?
Natural Cork is the bark of the cork oak (Quercus suber), a closed-cell natural cellular material available as natural sheet and stopper stock (NAT), resin-bonded agglomerate (AGG), expanded insulation corkboard (ICB) and cork-rubber grades (CR). It is chosen for compressibility, recovery and vibration and sound damping at a density of only 0.16 g/cm3, with thermal conductivity 0.045 W/m·K; forms include sheet, roll, block, punched discs and turned or moulded profiles. Strength is low (tensile 1.1 MPa, modulus 0.02 GPa) and service temperature is limited to 120 °C, and the surface stays porous unless sealed. For oil-resistant gaskets that must hold bolt load, use cork-rubber composition to ASTM F104. Natural Cork has a density of 0.16 g/cm³ (0.0058 lb/in³), lighter than 98% of natural material grades. Natural Cork has a tensile strength of 1 MPa (0.16 ksi), weaker than 99% of natural material grades. Elongation at break is 7% and the elastic modulus is 0.02 GPa (0.0029 Msi).
What is Natural Cork used for?
- gaskets
- bottle stoppers
- flooring underlayment
- vibration isolation pads
- bulletin boards
Advantages
- Lightweight — 0.16 g/cm³ (0.0058 lb/in³), better than 98% of natural material grades
- Good corrosion resistance — 75/100, better than 81% of natural material grades
- High service temperature — 120°C (248 °F), better than 79% of natural material grades
- Low embodied carbon — 0.3 kg CO₂/kg, better than 79% of natural material grades
- Ductile — tolerates forming and impact — 7%, better than 78% of natural material grades
Limitations
- Poor heat conductor — 0.05 W/m·K (0.026 BTU/hr·ft·°F), worse than 99% of natural material grades
- Hard to polish — 10/100, worse than 99% of natural material grades
- Low stiffness — 0.02 GPa (0.0029 Msi), worse than 93% of natural material grades
Natural Cork properties
Typical room-temperature values; bars are the position among natural material grades.
Physical2
Natural Cork has a density of 0.16 g/cm³ (0.0058 lb/in³), lighter than 98% of natural material grades.
Mechanical9
Natural Cork has a tensile strength of 1 MPa (0.16 ksi), weaker than 99% of natural material grades. Elongation at break is 7% and the elastic modulus is 0.02 GPa (0.0029 Msi).
Thermal4
Natural Cork is rated for continuous service to 120°C (248 °F). It conducts heat at 0.05 W/m·K (0.026 BTU/hr·ft·°F), worse than 99% of natural material grades.
Electrical1
Natural Cork has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental1
Corrosion resistance is very good (75/100), better than 81% of natural material grades.
Sustainability4
Producing a kilogram of Natural Cork takes about 5 MJ of energy and emits 0.3 kg of CO₂ — less than 81% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Natural Cork's machinability is excellent (85/100, better than 63% of natural material grades).
Common Calculations3
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Working with Natural Cork
Is Natural Cork easy to machine?
Die-cut, punched, band-sawn or laser-cut with sharp tooling and high speed; dust extraction required, no coolant.
Can Natural Cork be welded?
Not weldable — join by contact adhesive, PU/PVAc glue or hot-melt; agglomerates are heat-pressed with resin.
Can Natural Cork be formed, bent or molded?
Granules are compression-moulded with binder or steam-expanded in autoclave blocks, then sliced into sheet or profile.
Natural Cork 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 |
|---|---|---|
| suberincross-linked fatty-acid polyester of the cell wall | 33 – 50 | 42 |
| lignin | 18 – 26 | 22 |
| polysaccharides (cellulose + hemicellulo | 12 – 25 | 19 |
| extractives (waxes, tannins) | 8 – 20 | 15 |
| ash + moisturebalance, varies with equilibrium moisture | ≥ 1 (balance) |
What surface finishes work on Natural Cork?
Sand lightly and seal with wax, PU or water-based lacquer; cannot be polished, surface will stay porous.
How much does Natural Cork cost?
Natural Cork is a premium-cost natural material ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Natural Cork — frequently asked
What is Natural Cork used for?
Natural Cork is typically used for gaskets, bottle stoppers, flooring underlayment, vibration isolation pads and bulletin boards. In short: lowest-density natural gasket material; best natural vibration damping; closed-cell, non-rotting.
What is the tensile strength of Natural Cork?
Natural Cork has a typical tensile strength of 1 MPa (0.16 ksi) — weaker than 99% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Natural Cork easy to machine?
Yes — machinability is rated excellent (85/100, better than 63% of natural material grades). Die-cut, punched, band-sawn or laser-cut with sharp tooling and high speed; dust extraction required, no coolant.
Can Natural Cork be welded?
Not weldable — join by contact adhesive, PU/PVAc glue or hot-melt; agglomerates are heat-pressed with resin.
What surface finishes work on Natural Cork?
Sand lightly and seal with wax, PU or water-based lacquer; cannot be polished, surface will stay porous.
Can Natural Cork be formed, bent or molded?
Granules are compression-moulded with binder or steam-expanded in autoclave blocks, then sliced into sheet or profile.
What is the maximum service temperature of Natural Cork?
Natural Cork is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Natural Cork cost?
Natural Cork is a premium-cost natural material ($$$), 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
- Cellular Solids: Structure and Properties, 2nd ed. — Cambridge University Press (Gibson & Ashby) (1997)
- Cork: properties, capabilities and applications (Int. Materials Reviews 50) — Taylor & Francis (Silva et al.) (2005)
- EN 13170 — Thermal insulation products: factory made expanded cork (ICB) — CEN (2012)
- ASTM F104 — Classification System for Nonmetallic Gasket Materials (cork and cork-rubber) — ASTM (2018)
- Amorim Cork Composites technical data sheets (agglomerated, expanded, cork-rubber) — Corticeira Amorim (2023)
- Materials and the Environment (embodied energy/CO2 of natural materials) — Butterworth-Heinemann (Ashby) (2021)
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.