Cork
Cork is a closed-cell natural cellular material harvested from cork oak bark, supplied as natural blocks (NAT), agglomerated board (AGG), expanded insulation corkboard (ICB) and rubber-cork compounds (CR).
Reference datasheet — 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.
Cork tempers and conditions
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) cork insulation board, EN 13170 | Steam-expanded granules self-bonded by their own suberin resin — binder-free, dimensionally stable insulation board for walls, roofs and cryogenic linings. | 0.09 | 0.04 W/m·K | |||
Agglomerated (composition) cork, resin-bonded granules | Cork granules bonded with PU/phenolic binder into sheet, roll or block — the standard choice for gaskets, underlayment and low-cost boards with uniform properties. | 0.9 | 5 | 0.05 W/m·K | ||
Cold rolled | Cork granules in an elastomer matrix (ASTM F104 style) — pick for oil-resistant, high-recovery sealing gaskets and anti-vibration pads at higher clamp loads. | 2 | 15 | 0.1 W/m·K |
Supply forms, finishes and certifications
Ways 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 Cork?
Cork is a closed-cell natural cellular material harvested from cork oak bark, supplied as natural blocks (NAT), agglomerated board (AGG), expanded insulation corkboard (ICB) and rubber-cork compounds (CR). It is used for elasticity, buoyancy, chemical inertness and thermal/acoustic insulation, with 0.16 g/cm³ density, 0.045 W/m·K conductivity, 1.1 MPa tensile strength, 7 % elongation and a very low 0.02 GPa modulus; service reaches 110 °C and chemical resistance is high (score 85). It carries no structural load, takes a compression set under sustained clamping, and stays porous unless sealed or rubber-faced. Closed-cell elastomer foam is the nearest alternative for pure sealing duty. Cork has a density of 0.16 g/cm³ (0.0058 lb/in³), lighter than 98% of natural material grades. 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 Cork used for?
- bottle stoppers
- gaskets and seals
- flooring underlayment
- insulation panels
- vibration/noise damping
Advantages
- Lightweight — 0.16 g/cm³ (0.0058 lb/in³), better than 98% of natural material grades
- Good corrosion resistance — 85/100, better than 90% 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 — 12/100, worse than 94% of natural material grades
- Low stiffness — 0.02 GPa (0.0029 Msi), worse than 93% of natural material grades
Cork properties
Typical room-temperature values; bars are the position among natural material grades.
Physical2
Cork has a density of 0.16 g/cm³ (0.0058 lb/in³), lighter than 98% of natural material grades.
Mechanical9
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).
Thermal5
Cork is rated for continuous service to 110°C (230 °F). It conducts heat at 0.05 W/m·K (0.026 BTU/hr·ft·°F), worse than 99% of natural material grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical1
Cork has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental1
Corrosion resistance is excellent (85/100), better than 90% of natural material grades.
Sustainability4
Producing a kilogram of Cork takes about 6 MJ of energy and emits 0.5 kg of CO₂ — less than 78% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Cork's machinability is very good (80/100, worse than 52% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Working with Cork
Is Cork easy to machine?
Die-cuts, punches, waterjets and CNC-routs easily with very sharp tools and vacuum hold-down; avoid high tool temperatures that scorch the suberin.
Can Cork be welded?
Not weldable — join by contact adhesive, PU/phenolic binder or elastomer bonding; expanded board is also mechanically fixed.
Can Cork be formed, bent or molded?
Boiled planks are punched or sliced; granules are hot-pressed with binder (agglomerated) or steam-expanded and self-bonded in autoclaves (ICB blocks) then sawn to size.
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, source of elasticity and impermeability | 33 – 50 | 42 |
| lignin | 18 – 26 | 22 |
| polysaccharides (cellulose + hemicellulo | 12 – 25 | 19 |
| extractives (waxes, tannins, ceroids) | 8 – 20 | 14 |
| ash / inorganics | 0.5 – 2.5 | 1.2 |
| moisture (as supplied)equilibrium moisture, affects density and resistivity | 4 – 9 | 6 |
What surface finishes work on Cork?
Sanding plus wax, shellac or PU sealer for floors; surfaces cannot be polished to gloss and stay porous unless sealed or rubber-faced.
Equivalent designations
Standards and trade names that resolve to Cork in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Quercus suber bark
How much does Cork cost?
Cork is a premium-cost natural material ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Cork — frequently asked
What is Cork used for?
Cork is typically used for bottle stoppers, gaskets and seals, flooring underlayment, insulation panels and vibration/noise damping. In short: lowest-modulus natural material; closed-cell and buoyant; strong natural damping.
What is the tensile strength of Cork?
Cork has a typical tensile strength of 1 MPa (0.16 ksi) — weaker than 99% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Cork easy to machine?
Yes — machinability is rated very good (80/100, worse than 52% of natural material grades). Die-cuts, punches, waterjets and CNC-routs easily with very sharp tools and vacuum hold-down; avoid high tool temperatures that scorch the suberin.
Can Cork be welded?
Not weldable — join by contact adhesive, PU/phenolic binder or elastomer bonding; expanded board is also mechanically fixed.
What surface finishes work on Cork?
Sanding plus wax, shellac or PU sealer for floors; surfaces cannot be polished to gloss and stay porous unless sealed or rubber-faced.
Can Cork be formed, bent or molded?
Boiled planks are punched or sliced; granules are hot-pressed with binder (agglomerated) or steam-expanded and self-bonded in autoclaves (ICB blocks) then sawn to size.
What is the maximum service temperature of Cork?
Cork is rated for continuous use to about 110°C (230 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Cork cost?
Cork is a premium-cost natural material ($$$), 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 (cork chapter) — Cambridge University Press (1997)
- Cork: Biology, Production and Uses — Elsevier (2007)
- EN 13170 — Thermal insulation products: factory made expanded cork (ICB) — CEN (2012)
- ASTM F104 — Classification System for Nonmetallic Gasket Materials — ASTM (2021)
- Expanded cork insulation board technical data — Amorim Cork Insulation (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.