Working with Niangon in Epoxy Tabletops
Niangon encompasses timber from the African species Heritiera densiflora, Tarrietia densiflora, Heritiera utilis, and Tarrietia utilis (the genera Heritiera and Tarrietia are synonymous). Sourced primarily from Côte d’Ivoire, Gabon, Ghana, Liberia, and Sierra Leone, this hardwood offers a distinctive visual character. According to the CIRAD Tropix technical sheet, the wood transitions from pink brown or purplish red brown to a rich bronze shade as it ages. It features a medium texture, slight interlocked grain, a large visible silver figure, and feels oily to the touch.
For epoxy river tables and hybrid furniture, Niangon brings impressive mechanical strength alongside specific working considerations, particularly regarding movement, tool wear, and surface preparation.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Heritiera densiflora (synonymous), Tarrietia densiflora, Heritiera utilis (synonymous), Tarrietia utilis | |
| Colour / texture / grain | Red brown; texture medium; grain interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.70 | about 43.7 lb/ft³; a 2-inch-thick slab weighs about 7.3 lb per sq ft |
| Monnin hardness (12% MC) | 3.8 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 8.8 % | green to oven-dry |
| Total radial shrinkage | 4.2 % | green to oven-dry |
| Ratio St/Sr | 2.1 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.45 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 32 % | |
| Thermal conductivity | 0.23 W/(m·K) | |
| Crushing strength (12% MC) | 55 MPa | about 7,980 psi |
| Static bending strength (12% MC) | 103 MPa | about 14,940 psi |
| Modulus of elasticity (12% MC) | 14,430 MPa | about 2,093,000 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 4 – not permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate rapid to normal; distortion: high risk; checking: 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 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). Notes. Genera Tarrietia and Heritiera are synonymous. |
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).
Pros and Cons for River Table Builds
Pros
- Striking Appearance: Develops an attractive bronze patina with age and exhibits a pronounced, large silver figure.
- Substantial Strength: Provides a crushing strength of 55 MPa (about 7,980 psi) and static bending strength of 103 MPa (about 14,940 psi).
- Manageable Density: At a specific gravity of 0.70 (about 43.7 lb/ft³), a 2-inch slab weighs approximately 7.3 lb per square foot, offering solid stability without excessive weight.
- Good Fastener Holding: Rated good for both nailing and screwing into structural table bases.
- Regulatory Clarity: Niangon is not listed in the CITES Appendices (Washington Convention 2025).
Cons
- High Distortion Risk During Drying: Thin sections and irregular or interlocked grain carry a severe risk of warping.
- Differential Movement: Tangential shrinkage is 8.8% compared to 4.2% radial shrinkage, yielding a shrinkage ratio of 2.1 that can stress rigid epoxy joints.
- Tool Wear and Overheating: Fairly high blunting effect with reported tendencies to clog and overheat cutters.
- Tearout Tendency: Interlocked grain creates a risk of tearing during planing and jointing.
- Natural Oils: The wood is oily to the touch, which demands thorough degreasing and sealing to prevent bonding failures.
Build Notes for Epoxy Craftsmen
Slab Selection
Niangon logs typically range from 70 to 90 cm in diameter, producing moderately wide live-edge slabs. The sapwood is clearly demarcated and spans 3 to 4 cm in thickness. Tarrietia densiflora sometimes displays irregular grain, whereas Tarrietia utilis has slightly lower mechanical values. When selecting live edges for an epoxy river, verify that the sapwood is sound; the heartwood offers class 3 moderate resistance to fungi, but the sapwood remains susceptible to dry-wood borers.
Drying and Movement
Niangon exhibits a rapid to normal drying rate with a slight risk of checking and no known risk of collapse or casehardening. However, distortion remains a critical hazard. CIRAD Tropix notes that thin sections with interlocked grain carry a high risk of distortion, recommending an initial surface drying phase prior to kiln drying. Suggested kiln schedule temperatures range from 55 to 65 °C (about 131 to 149 °F).
The wood has a fibre saturation point of 32% and a coefficient of volumetric shrinkage of 0.45% per 1% change in moisture content. The total tangential shrinkage of 8.8% paired with a 2.1 St/Sr ratio means plainsawn boards will cup more readily than quartersawn stock. To prevent edge separation or shear fractures along your epoxy bond line, slabs must be dried thoroughly to interior equilibrium moisture content before pouring resin.
Machining and Hardness
On the French Monnin hardness scale, Niangon rates at 3.8 at 12% moisture content (where higher numbers reflect harder wood; this is not a Janka value). The wood causes fairly high tool blunting. Standard high-speed steel dulls rapidly; machine slabs using stellite-tipped saw teeth and tungsten carbide cutting knives. Machinists should also watch for resinous clogging, cutter overheating, and tearout along interlocked grain lines.
Sealing and Finishing
Because Niangon is naturally oily to the touch, resin adhesion requires careful surface preparation. Wipe the joint edges clean with an appropriate solvent and apply a thin epoxy seal coat before casting the main river. CIRAD Tropix specifically notes that filling is recommended to achieve a smooth, high-quality finish over its medium-textured pores.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: In addition to high-class cabinetwork and furniture components, CIRAD Tropix lists Niangon as resistant to one or several acids and notes end-uses including interior staircases, moulding, and ship building decks. (Source: CIRAD Tropix 7 technical sheet: Niangon.)