An Overview of Idigbo for Epoxy Tabletops
Idigbo (Terminalia ivorensis) is an African hardwood utilized across various woodworking disciplines, including furniture, cabinetry, and panelling. According to the CIRAD Tropix technical sheet for Idigbo, it is a medium-density hardwood exhibiting distinct mechanical and physical behaviors that woodworkers must understand before embedding it in clear epoxy resin.
When planning an epoxy river table or a hybrid wood-resin tabletop, wood stability, hardness, grain interaction, and chemical properties dictate the build approach. This guide examines how the laboratory findings for Idigbo translate to shop practices on the bench.
Appearance, Figure, and Slab Quality
Idigbo heartwood presents a yellow coloration that can be more or less light, occasionally displaying greenish shades. The sapwood measures from 2 to 5 cm thick and is not clearly demarcated from the heartwood. Idigbo logs typically range from 65 to 85 cm in diameter.
The wood has a medium texture and a grain that runs straight to slightly interlocked. When flatsawn or quartersawn, the slight interlock creates a ribbon-like aspect across the face of the board. When selecting live-edge slabs or boards, builders must watch for specific natural growth defects highlighted by CIRAD: Idigbo is prone to brittleheart at the center of the log and can contain wind shakes. Any areas affected by brittleheart or internal shakes should be trimmed away or stabilized with liquid epoxy before the primary river pour.
Density, Weight, and Hardness
Idigbo has an average specific gravity of 0.50 at 12% moisture content. In working shop terms, this corresponds to an air-dry density of about 31.2 lb/ft³, meaning a 2-inch-thick slab weighs roughly 5.2 lb per sq ft. This makes Idigbo noticeably lighter than heavy tropical species, producing manageable tabletops that do not require overbuilt steel leg assemblies.
On the French Monnin hardness scale, Idigbo rates at 1.9 at 12% moisture content. The Monnin test is a standardized metric where a higher numerical value indicates harder wood; it should never be equated to or converted into a Janka score. A Monnin rating of 1.9 indicates a moderately soft to medium-density surface. For dining tables or high-traffic furniture, builders should be aware that it can dent under point loads more readily than denser furniture hardwoods.
Dimensional Stability Next to an Epoxy River
Because cured epoxy resin does not expand or contract with ambient humidity, pairing it with wood requires low, predictable dimensional movement. Idigbo performs remarkably well in this category:
- Total tangential shrinkage: 5.2%
- Total radial shrinkage: 3.6%
- Shrinkage ratio (St/Sr): 1.4
- Coefficient of volumetric shrinkage: 0.37% per % MC
- Fibre saturation point: 27%
A tangential-to-radial ratio of 1.4 is close to 1.0, signifying minimal tendency to warp, cup, or twist across the grain. Combined with a modest volumetric shrinkage coefficient of 0.37%, Idigbo exerts relatively low shear stress against the resin bondline during normal indoor seasonal shifts.
Drying Characteristics
CIRAD records Idigbo as having a rapid drying rate. Remarkably, drying carries no risk or very slight risk of distortion, and no risk or very slight risk of surface checking. Furthermore, there is no known specific risk of internal collapse or casehardening. Kiln drying programs suggest temperatures running between 60 and 70 °C (about 140 to 158 °F). As always, wood must be verified at a uniform interior target moisture content before sealing and pouring epoxy.
Machining, Gluing, and Surface Preparation
Machining Idigbo requires normal tool upkeep. Saw teeth made of ordinary or alloy steel and standard cutting tools work well, as blunting effects are normal. However, due to the slight interlocked grain, builders face a risk of grain tearing during surfacing, jointing, or routing. Working with sharp edges and moderate feed rates minimizes tearout.
Additional shop considerations include:
- Health and dust: The CIRAD data sheet warns that Idigbo sawdust may cause irritations, making personal dust collection and protection important.
- Gluing and acidity: CIRAD notes that the wood is fairly acid, which must be taken into account when gluing because it has a tendency to stain. Clean prep surfaces thoroughly.
- Grain filling: Idigbo has a medium texture, and CIRAD notes that pore filling is necessary to obtain a smooth, high-quality finish.
- Fasteners: Nailing and screwing properties are rated as good.
Durability and Regulations
Idigbo heartwood falls into durability class 2 to 3 against wood-decay fungi, representing durable to moderately durable performance. However, it is rated as Class S (susceptible) to dry-wood borers throughout the entire wood, and Class S against termites. Heartwood treatability is Class 4 (not permeable). The wood is listed in European standard NF EN 350 (2016) and falls into Use Class 2 (interior or under cover where dampness is possible). Idigbo is not listed in the CITES Appendices (Washington Convention 2025).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Terminalia ivorensis | |
| Colour / texture / grain | Yellow; 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) | 1.9 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 5.2 % | green to oven-dry |
| Total radial shrinkage | 3.6 % | green to oven-dry |
| Ratio St/Sr | 1.4 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.37 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 27 % | |
| Thermal conductivity | 0.18 W/(m·K) | |
| Crushing strength (12% MC) | 44 MPa | about 6,380 psi |
| Static bending strength (12% MC) | 71 MPa | about 10,300 psi |
| Modulus of elasticity (12% MC) | 11,350 MPa | about 1,646,000 psi |
| Decay (fungi) resistance | Durability class 2 to 3 – durable to moderately durable | |
| Termite resistance | Class S – susceptible | |
| Dry-wood borer resistance | Class S – susceptible (risk in all the wood) | |
| Heartwood treatability | Class 4 – not permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate rapid; distortion: no risk or very slight risk; checking: no risk or very slight risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 60–70 °C | about 140–158 °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?
Idigbo is an excellent candidate for indoor epoxy river tables. Its 1.4 shrinkage ratio and low total movement protect the structural integrity of the wood-to-resin bondline, while its rapid drying with minimal checking or distortion keeps slabs flat. Builders simply need to inspect slabs for brittleheart, manage tearout around interlocked grain, prepare for its acidity during adhesive stages, and fill the medium pores to achieve an even tabletop finish.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: When breaking down Idigbo slabs, pay close attention to the center heartwood. CIRAD notes a known occurrence of brittleheart and internal wind shakes in this species; defective, crumbly heart centers must be fully routed out and structurally bridged rather than merely coated over. (Source: CIRAD Tropix 7 technical sheet: Idigbo.)