An Overview of Gedu Nohor for River Table Builders
Gedu nohor represents timber harvested from three closely related African species of the genus Entandrophragma: Entandrophragma angolense, Entandrophragma congoense, and Entandrophragma excelsum. Known in the trade under names such as Acuminata and Tiama mahogani, this timber originates across West and Central Africa. In fine woodworking and architectural millwork, it serves in cabinetwork for high-class furniture, interior joinery, panelling, flooring, staircases, and even boat planking and deck work.
For woodworkers crafting custom epoxy river tables and hybrid tabletops, Gedu nohor presents deep visual warmth alongside specific technical behaviors documented in the technical research published by CIRAD Tropix. Understanding its grain direction, movement rates, and surface characteristics ensures a secure, long-lasting bond when paired with deep-pour epoxy resin systems.
Wood Appearance, Weight, and Hardness
The heartwood of Gedu nohor displays a rich red-brown to dark brown coloration accentuated with golden shades. Its texture is medium, while its sapwood measures between 6 to 10 cm thick and is clearly demarcated from the heartwood. A defining structural characteristic of Gedu nohor is its marked interlocked grain, which yields shifting ribbon-like luster across slab faces.
In terms of weight, mature wood has an average specific gravity of 0.55 at 12% moisture content. That places its density at approximately 34.3 lb/ft³, meaning a 2-inch-thick slab weighs roughly 5.7 lb per square foot. This moderate density provides solid tabletop heft without excessive physical bulk during shop handling.
When evaluating surface crush resistance, the CIRAD Tropix technical sheet reports a Monnin hardness of 2.2 at 12% moisture content. The Monnin index is an established French metric hardness scale where a higher number denotes a harder surface. It is distinct from the North American Janka ball indentation scale and should never be converted into Janka values. With a Monnin score of 2.2 and a crushing strength of 47 MPa (about 6,820 psi), Gedu nohor offers moderate resistance to everyday tabletop contact.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Entandrophragma angolense, Entandrophragma congoense, Entandrophragma excelsum | |
| Other trade names | Acuminata, Tiama mahogani | |
| Colour / texture / grain | Red brown; texture medium; grain interlocked; interlocked grain marked | |
| Specific gravity (12% MC) | 0.55 | about 34.3 lb/ft³; a 2-inch-thick slab weighs about 5.7 lb per sq ft |
| Monnin hardness (12% MC) | 2.2 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 8.0 % | green to oven-dry |
| Total radial shrinkage | 4.6 % | green to oven-dry |
| Ratio St/Sr | 1.7 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.41 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 32 % | |
| Thermal conductivity | 0.19 W/(m·K) | |
| Crushing strength (12% MC) | 47 MPa | about 6,820 psi |
| Static bending strength (12% MC) | 80 MPa | about 11,600 psi |
| Modulus of elasticity (12% MC) | 10,980 MPa | about 1,593,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class S – susceptible | |
| Dry-wood borer resistance | Class D – durable (sapwood demarcated, risk limited | |
| Heartwood treatability | Class 4 – not permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate normal; distortion: high risk; checking: high 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).
Shrinkage and Movement Next to an Epoxy River
When embedding wood slabs alongside a rigid epoxy casting, shrinkage behavior is critical. Gedu nohor has a fibre saturation point of 32%. Shrinking from green down to oven-dry yields a total tangential shrinkage of 8.0% and a total radial shrinkage of 4.6%. The tangential-to-radial shrinkage ratio is 1.7, while the coefficient of volumetric shrinkage is 0.41% per 1% change in moisture content.
A ratio of 1.7 indicates moderate differential movement across grain orientations. In a river table design, live edges must be stabilized at equilibrium moisture content prior to casting. If the moisture shifts drastically post-pour, tangential pull across the epoxy boundary can stress the bond line. Maintaining stable indoor moisture levels prevents the 0.41% volumetric shift from pulling against the resin channel.
Pros and Cons for Wood and Epoxy Projects
- Pros: Attractive red-brown color with golden shades; marked interlocked grain creates eye-catching surface figure; moderate density (about 34.3 lb/ft³) keeps large conference tables manageable; good nail and screw holding; not listed under CITES restrictions (Washington Convention 2025).
- Cons: High risk of checking and high risk of distortion during drying; marked interlocked grain tears easily during surface planing unless tool angles are modified; tends to burn in mortising; heartwood is susceptible to termites (Class S); heartwood treatability is Class 4 (not permeable).
Build Notes: From Slab Prep to Final Finish
Slab Selection and Inspection
Logs range from 80 to 120 cm in diameter, yielding broad slabs for wide dining tables. Because the sapwood is clearly demarcated and spans 6 to 10 cm, builders can choose whether to retain the lighter live edge along the river wall or trim it away. Heartwood is classified as Durability Class 3 (moderately durable against xylophagous fungi) and Class D for dry-wood borers, with borer risks limited strictly to the sapwood.
Drying Considerations
According to CIRAD Tropix, the drying rate is normal, with no known specific risk for collapse or casehardening. However, both distortion and checking present a high risk. The presence of highly interlocked grain demands strict adherence to controlled drying parameters—such as kiln temperatures between 55 °C and 65 °C (131 °F to 149 °F)—to minimize severe twisting, cupping, or face checks before flattening.
Machining and Joinery
Machining Gedu nohor presents normal blunting effects on tools, allowing the use of ordinary or alloy steel sawteeth and standard cutters. However, because the interlocked grain is marked, planing requires a reduced cutting angle of 15° to prevent torn grain on the surface. Take extra care during joinery, as the wood tends to burn during mortising operations.
Sealing and Epoxy Pours
The medium texture and Class 4 impermeable heartwood require clean mechanical preparation along the river interface. Always follow the resin maker’s data sheet for surface preparation, working temperature, and seal coat application. Brushing a thin, thoroughly mixed barrier coat onto the edge seals surface voids and reduces bubble outgassing into deep pours.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: In structural evaluations under French standard NF B 52-001-1 (2018), visual grading can assign Gedu nohor to strength class D18, supported by its static bending strength of 80 MPa (about 11,600 psi) and modulus of elasticity of 10,980 MPa (about 1,593,000 psi). (Source: CIRAD Tropix 7 technical sheet: Gedu nohor.)