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Iroko Wood
Iroko Wood
Iroko wood, also known as Kambala, is a durable and versatile hardwood species derived from the Chlorophora regia and Chlorophora excelsa trees. This wood is valued for its aesthetic qualities, strength, and resistance to weather conditions, making it suitable for both indoor and outdoor applications.
Origin
Iroko comes from various parts of West and Central Africa. The two main botanical species that provide Iroko wood are:
- Chlorophora regia: Primarily found in the wet areas of the West African rainforest, from Gambia to Ghana.
- Chlorophora excelsa: Grows in areas with more leaf loss, from Senegal to Mozambique.
| Botanical Name | Growing Area |
|---|---|
| Chlorophora regia | From Gambia to Ghana |
| Chlorophora excelsa | From Senegal to Mozambique |
Appearance and Structure
Iroko is a light wood that rejuvenates well naturally, especially in open areas such as along logging roads or places with sparse vegetation.
- Heartwood: Golden brown, darkening to dark brown when exposed to air. The heartwood has a uniform structure and a moderately fine grain.
- Sapwood: Yellow-white, clearly distinct from the heartwood.
- Texture: Moderately fine grain with a straight to interlocked grain, sometimes wavy. The growth rings and light parenchyma traces around the wood vessels are clearly visible.
Durability
Iroko wood is very durable to durable (natural durability class I-II). The heartwood is resistant to acids and bases, while the sapwood is less durable (natural durability class V).
Physical Properties
| Property | Value |
|---|---|
| Average Density | 650 kg/m³ |
| Radial Shrinkage (60-30% r.h.) | 0.4% |
| Tangential Shrinkage (90-60% r.h.) | 0.8% |
| Bending Strength | 94 N/mm² |
| Modulus of Elasticity | 11,000 N/mm² |
| Compressive Strength (parallel to the grain) | 53 N/mm² |
| Hardness (Janka) | 5,600 N |
Drying and Moisture Content
Iroko dries relatively quickly, both accelerated and air-dried. However, there is a risk of cracking and warping, especially with interlocked grain. After sawing, Iroko is often shipped directly without drying, which can sometimes leave dark streaks on the wood from the stacking battens.
Workability
Iroko is well workable, both machine and hand tools. However, heart cracks may contain extremely hard white lime inclusions that can dull the tools.
| Machining Aspect | Comments |
|---|---|
| Machine Planing | Angle of 20° for circular saw, 15° for tungsten carbide. |
| Fine Sawdust and Sanding Dust | Can cause allergic reactions. Use good dust extraction. |
| Nailing and Screwing | Pre-drilling necessary; stainless fasteners recommended. |
| Gluing | Works well with all common types of adhesives. |
Finishing
Iroko for outdoor applications often remains untreated and naturally grays over time. For a better finish, synthetic resins such as cellulose vinyl paint or polyurethane varnish can be used.
Applications
Thanks to its durability and aesthetic qualities, Iroko is suitable for a wide range of applications:
- Outdoor Structures: Exterior joinery, cladding, garden furniture.
- Industrial Applications: Container bottoms, laboratory tables.
- Decorative: Parquet, stairs.
Conclusion
Iroko wood is a durable and versatile hardwood species that is ideal for a wide range of applications, both indoors and outdoors. It offers excellent workability, aesthetic appeal, and long-lasting performance.