Tropical wood · Tropical America
Hura wood
Hura (Hura crepitans, family Euphorbiaceae) is a tropical timber from tropical America. Dry, its Janka hardness is 550 lbf (2,447 N), and air-dry it weighs about 25–28 lb/ft³ (400–449 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 167–168.
Other names, by country: Arbol del diablo, Haba (Mexico), Jabillo (Central America), Ceiba amarilla, Ceiba de leche (Colombia), Ceiba blanca, Ceiba habillo (Venezuela), Assacú, Açacu (Brazil).
Key numbers
- Janka hardness, dry
- 550 lbf (2,447 N)
- Green: 440 lbf (1,957 N)
- As printed: “Janka side hardness 440 lb for green material and 550 lb at 12% moisture content.”
- Air-dry density
- 25–28 lb/ft³ (400–449 kg/m³)
- Basic specific gravity
- 0.33–0.38 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) 0.33 to 0.38; air-dry density 25 to 28 pcf.”
- Shrinkage, green to oven-dry
- 4.5% tangential
- Radial 2.7%, volumetric 7.3%
One source: USDA Forest Products Laboratory, Tropical Timbers of the World (Chudnoff, 1979 edition), the only published source read for this wood
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE); crushing strength is compression parallel to the grain. The sheet collects these from published tests: it prints 5 data sets, from different tests and sources, so they can differ widely; all are shown, in the sheet's order, each at the moisture content printed beside it, never restated as 12%.
| Moisture | Bending strength (MOR) | Stiffness (MOE) | Crushing strength |
|---|---|---|---|
| Green | 6,310 psi (44 MPa) | 1.04 million psi (7.2 GPa) | 2,790 psi (19 MPa) |
| 12% MC | 8,710 psi (60 MPa) | 1.17 million psi (8.1 GPa) | 4,800 psi (33 MPa) |
| Green | 5,100 psi (35 MPa) | 0.82 million psi (5.7 GPa) | 2,270 psi (16 MPa) |
| 15% MC | 8,000 psi (55 MPa) | — | 3,860 psi (27 MPa) |
| 12% MC | 7,050 psi (49 MPa) | 0.9 million psi (6.2 GPa) | — |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Heartwood pale yellowish-brown or pale olive-gray; sapwood yellowish-white often indistinct from heartwood. Texture fine to medium; luster high; grain straight to interlocked, without distinctive odor or taste.
- Working properties
- The wood usually machines easily but green material is somewhat difficult to work due to tension wood, resulting in fuzzy surfaces. The wood finishes well and is easy to glue and nail.
- Durability
- The wood is reported to be very variable in resistance to attack by decay fungi; highly susceptible to bluestain and very susceptible to dry-wood termites.
- Uses
- General carpentry, boxes and crates, veneer and plywood, joinery, furniture, fiberboard, and particleboard.
- Where it grows
- Throughout the West Indies and from Central America to northern Brazil and Bolivia. Often occurs in nearly pure stands in Surinam on moist sandy loam. Frequently cultivated for shade.
Quoted from Tropical Timbers of the World, pp. 167–168, a USDA Forest Products Laboratory work in the public domain.
Work it out for your project
- Rank woods for furniture with the species picker
Weigh hura against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.