Tropical wood · Africa
Yellow Sterculia wood
Yellow Sterculia (Sterculia oblonga, family Sterculiaceae) is a tropical timber from Africa. Dry, its Janka hardness is 1,120 lbf (4,982 N), and air-dry it weighs about 48 lb/ft³ (769 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 509–510.
Other names, by country: Okoko (Nigeria), Bi (Ivory Coast), Eyong, Bongele (Cameroon), N'chong (Gabon).
Key numbers
- Janka hardness, dry
- 1,120 lbf (4,982 N)
- Green: 880 lbf (3,914 N)
- As printed: “Janka side hardness 880 lb for green and 1,120 lb for dry material.”
- Air-dry density
- 48 lb/ft³ (769 kg/m³)
- Basic specific gravity
- 0.61 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) 0.61; air-dry density 48 pcf.”
- Shrinkage, green to oven-dry
- 10.8% tangential
- Radial 4.5%, volumetric 14.2%
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 3 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 | 11,700 psi (81 MPa) | 1.5 million psi (10.3 GPa) | 5,610 psi (39 MPa) |
| 12% MC | 17,900 psi (123 MPa) | 1.98 million psi (13.7 GPa) | 9,750 psi (67 MPa) |
| 12% MC | 17,700 psi (122 MPa) | 1.93 million psi (13.3 GPa) | 9,400 psi (65 MPa) |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Heartwood creamy-white to light yellowish-brown; sapwood 4-8 in. wide, pale in color and not clearly demarcated. Texture rather coarse; grain shallowly interlocked; freshly cut wood has a disagreeable odor which does not persist; high rays produce an attractive lustrous figure on quartersawn stock.
- Working properties
- Works rather well with machine tools but difficult to work with hand tools, blunting of cutting edges is moderate, a cutting angle of 20 degrees is suggested to reduce grain tear in planing; nailing and gluing satisfactory; moderate steam-bending properties.
- Durability
- Heartwood is nondurable and not resistant to termite attack; sapwood liable to powder-post beetle attack and stain.
- Uses
- Construction work where durability is not required, decorative veneer, flooring, furniture components.
- Where it grows
- Tropical West African forests from Liberia to Gabon, found in the transition zone between the humid evergreen and semideciduous forests as well as secondary forests.
Quoted from Tropical Timbers of the World, pp. 509–510, 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 yellow Sterculia against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.