Balsa HD (High density select)
Supply condition
Choose the ~0.22 g/cm³ select cut for parts with local bearing, bolt or insert areas and higher shear loads, trading roughly double the weight of low-density stock.
Values for the HD condition
Other Balsa tempers and conditions
Balsa is listed in 4 conditions; see the grade overview at Balsa.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
end-grain balsa sandwich core block (SB/AL series, ~0.15 g/cm³) | Use blocks cut and assembled with the fibres perpendicular to the panel face for wind-blade, hull and flooring sandwich cores; through-thickness compression and shear far exceed flat-grain sheet. | — | 12 | 1 | — | 0.06 W/m·K |
Low density select | Pick for weight-critical, lightly loaded parts — indoor models, racing wing ribs, ultralight filler cores — accepting the lowest strength and stiffness of the density selections. | — | 14 | 1.3 | — | 0.04 W/m·K |
Green / unseasoned | Treat freshly sawn stock above fibre saturation as an intermediate state before drying only; strength and stiffness are clearly below those of the dried material. | — | 17 | 2.2 | — | 0.11 W/m·K |
HDThis page High density select | Choose the ~0.22 g/cm³ select cut for parts with local bearing, bolt or insert areas and higher shear loads, trading roughly double the weight of low-density stock. | — | 34 | 1.8 | — | 0.07 W/m·K |
What is Balsa HD?
Balsa HD is Balsa supplied in the HD condition — choose the ~0.22 g/cm³ select cut for parts with local bearing, bolt or insert areas and higher shear loads, trading roughly double the weight of low-density stock. Balsa HD has a tensile strength of 34 MPa (4.93 ksi), stronger than 62% of natural material grades. Elongation at break is 1.8% and the elastic modulus is 5 GPa (0.725 Msi). Balsa HD has a density of 0.22 g/cm³ (0.0079 lb/in³), lighter than 94% of natural material grades.
Advantages
- Lightweight — 0.22 g/cm³ (0.0079 lb/in³), better than 94% of natural material grades
- Ductile — tolerates forming and impact — 1.8%, better than 77% of natural material grades
Limitations
- Low fracture toughness — 0.22 MPa·√m (0.2 ksi·√in), worse than 97% of natural material grades
- Poor heat conductor — 0.07 W/m·K (0.0393 BTU/hr·ft·°F), worse than 87% of natural material grades
- Hard to polish — 20/100, worse than 85% of natural material grades
Balsa HD properties
Typical room-temperature values for Balsa HD; 13 are specific to this condition. Other listed values are Balsa reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Balsa HD has a density of 0.22 g/cm³ (0.0079 lb/in³), lighter than 94% of natural material grades.
Mechanical9
Balsa HD has a tensile strength of 34 MPa (4.93 ksi), stronger than 62% of natural material grades. Elongation at break is 1.8% and the elastic modulus is 5 GPa (0.725 Msi).
Thermal5
Balsa HD is rated for continuous service to 90°C (194 °F). It conducts heat at 0.07 W/m·K (0.0393 BTU/hr·ft·°F), worse than 87% of natural material grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical1
Balsa HD has an electrical resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental1
Corrosion resistance is poor (33/100), worse than 68% of natural material grades.
Sustainability4
Producing a kilogram of Balsa HD takes about 8 MJ of energy and emits 0.45 kg of CO₂ — less than 74% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Balsa HD's machinability is excellent (85/100, better than 63% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Balsa HD
Is Balsa easy to machine?
Cuts easily with sharp tooling at high spindle speed and light feed; blunt edges or excessive clamping pressure crush the cell structure, and laser cutting and steel-rule die cutting are both common.
Can Balsa be welded?
Not weldable; structural joints rely on epoxy, polyurethane or PVA adhesive, and end-grain core is co-cured bonded to the skins.
Can Balsa be formed, bent or molded?
Thin sheet softened with steam or hot water bends to small radii; thicker stock is shaped by block jointing or by laminating and gluing layers.
What surface finishes work on Balsa?
Seal the surface first with sanding sealer, thinned epoxy or heat-shrink film, otherwise the wood absorbs large amounts of water and resin and will not sand to a flat surface.
Balsa 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 |
|---|---|---|
| cellulosecellulose, main load-bearing phase | 38 – 48 | 43 |
| hemicellulosehemicellulose | 20 – 30 | 25 |
| ligninlignin | 18 – 26 | 22 |
| extractives + ashextractives and ash | 1 – 6 | 3 |
| moisturekiln-dried equilibrium moisture content | 6 – 14 | 10 |
Balsa HD — frequently asked
What is Balsa HD used for?
Balsa HD is typically used for model aircraft, surfboard cores, sandwich panel cores, thermal/acoustic insulation and buoyancy floats. In short: lowest-density structural wood; highest stiffness-to-weight timber; standard end-grain sandwich core.
What is the tensile strength of Balsa HD?
Balsa HD has a typical tensile strength of 34 MPa (4.93 ksi) — stronger than 62% of natural material grades. Strength varies by condition: see the 4 listed tempers.
Is Balsa HD easy to machine?
Yes — machinability is rated excellent (85/100, better than 63% of natural material grades). Cuts easily with sharp tooling at high spindle speed and light feed; blunt edges or excessive clamping pressure crush the cell structure, and laser cutting and steel-rule die cutting are both common.
Can Balsa HD be welded?
Not weldable; structural joints rely on epoxy, polyurethane or PVA adhesive, and end-grain core is co-cured bonded to the skins.
What surface finishes work on Balsa HD?
Seal the surface first with sanding sealer, thinned epoxy or heat-shrink film, otherwise the wood absorbs large amounts of water and resin and will not sand to a flat surface.
Can Balsa HD be formed, bent or molded?
Thin sheet softened with steam or hot water bends to small radii; thicker stock is shaped by block jointing or by laminating and gluing layers.
What is the maximum service temperature of Balsa HD?
Balsa HD is rated for continuous use to about 90°C (194 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Wood Handbook — Wood as an Engineering Material, FPL-GTR-190 — USDA Forest Products Laboratory (2021)
- ASTM D143 — Standard Test Methods for Small Clear Specimens of Timber — ASTM International (2022)
- BALTEK SB / AL End-Grain Balsa Core Data Sheets — 3A Composites Core Materials (2021)
- Cellular Solids: Structure and Properties — Gibson & Ashby, 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.