African Cordia as a River Table Wood
African cordia represents several closely related timber species across Africa, primarily Cordia africana (synonymous with Cordia abyssinica and Cordia holstii), Cordia millenii, and Cordia platythyrsa. Known in furniture production for fine cabinetwork, it presents a distinct set of physical characteristics that make it an appealing candidate for solid wood tabletops and epoxy river projects.
According to research published in the CIRAD Tropix technical database, African cordia produces heartwood that ranges from light brown to pale golden brown, occasionally displaying pinkish-brown undertones. The wood exhibits a medium to coarse texture with straight or slightly interlocked grain. Freshly cut green wood possesses an aromatic odour. When selecting raw slabs or boards, builders will find that logs typically span from 50 to 100 cm in diameter, though the sapwood—which measures between 4 and 6 cm thick—is not clearly demarcated from the heartwood.
Weight and Hardness Considerations
African cordia is a moderate-density hardwood. At a standard 12% moisture content, it has an average specific gravity of 0.50, translating to a density of approximately 31.2 lb/ft³. For table makers calculating base support requirements and handling loads, a 2-inch-thick tabletop slab weighs approximately 5.2 lb per square foot.
Mechanical resistance is measured in the CIRAD Tropix data using the French Monnin hardness test rather than the North American Janka test. On the Monnin scale, a higher number signifies a harder wood surface. African cordia registers a Monnin hardness of 1.3. This places it in the softer category of cabinet hardwoods. While this makes the timber easy to handle, builders should note that tabletops subjected to heavy daily contact may show surface indentations more readily than dense hardwoods, unless guarded by a protective film or finish.
Shrinkage and Stability Next to Epoxy
Dimensional stability is the most critical factor when locking wood edges against a rigid epoxy river. Uneven expansion or excessive seasonal movement can stress adhesive interfaces or cause warping across a wide tabletop. African cordia performs exceptionally well in this regard.
Its shrinkage values from green to oven-dry moisture states are relatively low:
- Total tangential shrinkage (St): 4.6%
- Total radial shrinkage (Sr): 3.4%
- Shrinkage ratio (St/Sr): 1.4
- Coefficient of volumetric shrinkage: 0.25% per 1% change in moisture content
The fibre saturation point sits at 31%. The modest tangential movement of 4.6% combined with a low St/Sr ratio of 1.4 indicates a wood with low cupping tendency and balanced movement across plainsawn and quartersawn orientations. With a volumetric shrinkage coefficient of only 0.25% per 1% change in moisture content, dried African cordia displays dependable dimensional stability inside climate-controlled living spaces, reducing shear forces at the epoxy bond line.
Drying Characteristics and Defect Risks
Proper drying is essential before pouring resin. The CIRAD Tropix data sheet reports that African cordia has a rapid drying rate. Despite drying quickly, the risk of degrade is remarkably low: there is only a slight risk of distortion, no risk or very slight risk of surface checking, and no known specific risk of casehardening or cell collapse. Recommended industrial kiln schedules employ temperatures ranging between 55 and 65 °C (about 131 to 149 °F), allowing the wood to shed moisture cleanly without creating hidden internal stress fractures.
Machining, Assembly, and Finishing
In the shop, African cordia is straightforward to process. Its blunting effect on cutters is rated as normal, requiring only ordinary cutting tools and ordinary or alloy steel saw teeth. The timber can be surfaced smoothly without demanding specialized carbide tooling, though care should be taken around areas of slight grain interlock.
Nailing and screwing properties are rated as good. For finishing, the CIRAD Tropix documentation notes that pore filling is recommended to achieve a smooth, high-quality surface due to its medium to coarse texture. In an epoxy build, filling or seal-coating open wood pores prior to the deep pour also minimizes the risk of outgassing and bubbling at the resin edge.
Natural Durability and Regulatory Status
African cordia heartwood offers moderate natural protection against biological hazards. It is categorized as Durability Class 3 (moderately durable) against xylophagous fungi, while demonstrating Class D (durable) performance against termites and dry-wood borers (with the caveat that sapwood is not clearly demarcated and lacks this borer resistance). Its heartwood treatability is Class 3 (poorly permeable). By natural durability criteria, it corresponds to Use Class 2 (interior or under cover, where dampness is possible).
Regarding international trade regulations, African cordia is not listed in the CITES Appendices under the Washington Convention (2025 updates), allowing for straightforward documentation and sourcing.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Cordia africana, Cordia abyssinica (synonymous), Cordia holstii (synonymous), Cordia millenii, Cordia platythyrsa, Cordia p.p. | |
| Colour / texture / grain | Light brown; texture medium; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.50 | about 31.2 lb/ft³; a 2-inch-thick slab weighs about 5.2 lb per sq ft |
| Monnin hardness (12% MC) | 1.3 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 4.6 % | green to oven-dry |
| Total radial shrinkage | 3.4 % | green to oven-dry |
| Ratio St/Sr | 1.4 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.25 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 31 % | |
| Thermal conductivity | 0.18 W/(m·K) | |
| Crushing strength (12% MC) | 38 MPa | about 5,510 psi |
| Static bending strength (12% MC) | 73 MPa | about 10,590 psi |
| Modulus of elasticity (12% MC) | 8,600 MPa | about 1,247,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class D – durable | |
| Dry-wood borer resistance | Class D – durable (heartw. durable but sapw. not | |
| Heartwood treatability | Class 3 – poorly permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate rapid; distortion: slight risk; checking: no risk or very slight risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 55–65 °C | about 131–149 °F |
| Machining | blunting normal; saw teeth: ordinary or alloy steel; cutting tools: ordinary | |
| Nailing and screwing | Good | |
| CITES status | This species is not listed in the CITES Appendices (Washington Convention 2025). |
Values from the CIRAD Tropix technical sheet (average values for mature wood, 12% moisture content where noted). US-unit conversions are calculated by BigEpoxy (1 MPa = 145.04 psi; density = specific gravity × 62.43 lb/ft³).
Is It a Good Epoxy Table Wood?
African cordia is an excellent timber for custom epoxy river tables and fine interior tabletops. Its standout strength lies in its low shrinkage figures (4.6% tangential, 3.4% radial) and low St/Sr ratio of 1.4, which ensure that dried slabs remain stable against cured epoxy resin. Furthermore, its rapid drying schedule without checking or collapse minimizes internal defects. The primary trade-off is surface hardness: with a Monnin hardness of 1.3, it is softer than typical dining table hardwoods, so using durable surface finishes and grain fillers is recommended to protect the tabletop over years of daily service.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Because CIRAD Tropix indicates that African cordia sapwood is not clearly demarcated and spans 4 to 6 cm thick without the heartwood’s natural resistance to dry-wood borers, examine slab live edges closely for insect pinholes before sealing and casting resin. (Source: CIRAD Tropix 7 technical sheet: African cordia.)