Introduction to Gheombi
Gheombi, botanically classified as Sindoropsis letestui (synonymous with Copaifera letestui), is a timber species native to Africa. Known for its warm coloration and substantial mechanical properties, it is documented in technical literature for furniture, interior joinery, and flooring. For craftsmen designing wood and epoxy resin river tables, understanding how Gheombi behaves during drying, machining, and seasonal moisture shifts is critical to preventing seam failure and tabletop distortion. All baseline physical metrics and working properties here are derived from the CIRAD Tropix technical sheet for mature Gheombi heartwood.
Appearance, Grain, and Slab Width Potential
Gheombi exhibits a distinctive pinkish brown heartwood marked with copper glints that darkens upon exposure to light. The sapwood is clearly demarcated from the heartwood and measures from 8 to 10 cm in thickness. The wood has a medium texture with grain that runs straight or interlocked, though interlocked grain is rated as slight. The CIRAD Tropix data notes the possible presence of wind shakes in flat sawn sections, as well as resin canals located mainly in the sapwood.
For builders sourcing live-edge slabs or wide planks, log diameter typically ranges from 70 to 100 cm. Because the sapwood is wide (from 8 to 10 cm on each side) and resin canals concentrate in that zone, CIRAD notes a low yield. When planning an epoxy river layout, builders should assess whether to include or trim this sapwood, especially given that resin canals can interfere with bonding.
Weight, Monnin Hardness, and Mechanical Strength
At 12% moisture content, Gheombi has a specific gravity of 0.72. On average, this translates to an air-dry density of about 44.9 lb/ft³, meaning a 2-inch-thick tabletop slab weighs approximately 7.5 lb per sq ft. This gives the wood substantial heft, creating a stable, heavy foundation for dining or conference tables.
On the French Monnin hardness test, Gheombi rates at 5.4. The Monnin scale is an established European penetration test where a higher number indicates greater resistance to indentation and a harder surface; it is entirely distinct from the North American Janka test and cannot be directly converted into Janka units. A Monnin hardness of 5.4 reflects a wood surface capable of resisting daily wear and dents in finished furniture. Its crushing strength reaches 61 MPa (about 8,850 psi), with a static bending strength of 115 MPa (about 16,680 psi) and a modulus of elasticity of 18,640 MPa (about 2,704,000 psi).
Shrinkage, Stability, and the Epoxy River Interface
Connecting solid timber slabs to an inflexible cured epoxy river requires strict attention to dimensional stability. When wood shrinks or swells unevenly across its width, tensile stress concentrates along the glued epoxy joint, risking shear failure or warping.
Gheombi has a total tangential shrinkage of 6.8% and a total radial shrinkage of 3.7%, yielding a tangential-to-radial shrinkage ratio (St/Sr) of 1.8. While a ratio below 2.0 indicates a moderate cupping tendency, the wood possesses a coefficient of volumetric shrinkage of 0.55% per % moisture content, with a fibre saturation point recorded at 22%. Because volumetric movement per percent of moisture change is relatively active, keeping wood equilibrium controlled in the shop prior to casting is critical.
Drying Behavior and Risks
According to CIRAD Tropix testing, Gheombi dries at a slow rate. Most importantly, it carries a high risk of distortion during seasoning, though checking risk is slight, and there is no known specific risk of collapse or casehardening. Standard industrial kiln schedules list temperature ranges from 53 to 65 °C (about 127 to 149 °F). Because distortion risk is elevated, slabs must be thoroughly stickered, uniformly weighted, and allowed to acclimate before flattening and resin pouring.
Machining, Resin Clogging, and Assembly
Working Gheombi demands robust tooling. The CIRAD technical sheet notes that the blunting effect on cutting tools is fairly high. Stellite-tipped teeth are recommended for band or circular sawing, and tungsten carbide cutters should be used for machining. Woodworkers must also account for two shop challenges:
- Tool Clogging: Natural resin can cause clogging of sawblades and cutting tools during dimensioning.
- Planing Tear-out: Irregular grain may result in a fuzzy surface during thickness planing, requiring light passes and clean sanding.
- Fastening: Nailing and screwing performance is rated as good.
Natural Durability, Treatability, and CITES Status
The heartwood of Gheombi shows moderate natural durability against wood-destroying organisms. Its fungal resistance falls under Durability class 3 (moderately durable). Resistance to termites is Class M (moderately durable), while dry-wood borer resistance is Class D (durable, with risk limited to the demarcated sapwood). Its heartwood treatability is Class 2 (moderately permeable), qualifying it naturally for Use class 2 (inside or under cover, where dampness is possible). Sourced material does not present international trade restrictions: the species is not listed in the CITES Appendices (Washington Convention 2025).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Sindoropsis letestui, Copaifera letestui (synonymous) | |
| Colour / texture / grain | Pinkish brown; texture medium; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.72 | about 44.9 lb/ft³; a 2-inch-thick slab weighs about 7.5 lb per sq ft |
| Monnin hardness (12% MC) | 5.4 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 6.8 % | green to oven-dry |
| Total radial shrinkage | 3.7 % | green to oven-dry |
| Ratio St/Sr | 1.8 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.55 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 22 % | |
| Thermal conductivity | 0.24 W/(m·K) | |
| Crushing strength (12% MC) | 61 MPa | about 8,850 psi |
| Static bending strength (12% MC) | 115 MPa | about 16,680 psi |
| Modulus of elasticity (12% MC) | 18,640 MPa | about 2,704,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class M – moderately durable | |
| Dry-wood borer resistance | Class D – durable (sapwood demarcated, risk limited | |
| Heartwood treatability | Class 2 – moderately permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate slow; distortion: high risk; checking: slight risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 53–65 °C | about 127–149 °F |
| Machining | blunting fairly high; saw teeth: stellite-tipped; cutting tools: tungsten carbide | |
| 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?
Gheombi can make an attractive and sturdy epoxy tabletop due to its warm pinkish-brown tone, copper glints, and solid Monnin hardness of 5.4. However, builders must manage two primary difficulties: a high risk of distortion during drying and natural resins that clog blades and concentrate inside the sapwood. If you source thoroughly dried, flat boards and remove or carefully seal the resinous sapwood zones before casting your epoxy river, Gheombi delivers a dependable, hard-wearing interior table surface.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Take extra care when evaluating flat-sawn Gheombi stock for structural table applications, as CIRAD explicitly records the potential presence of internal wind shakes that could undermine slab integrity along the epoxy river channel. (Source: CIRAD Tropix 7 technical sheet: Gheombi.)