Introduction to Sepetir for Epoxy River Tables
Sepetir encompasses several timber species within the Leguminosae family from Asia-Oceania, primarily Pseudosindora palustris (synonymous with Copaifera palustris) as well as Sindora leiocarpa, Sindora siamensis, Sindora sumatrana, Sindora velutina, and other Sindora species. Recognized in fine woodworking as an attractive substitute for Walnut, it yields distinct heartwood marked by dark striping, making it an eye-catching option for wood and epoxy tabletops. However, its natural resin content and physical movement demand careful handling in the shop.
According to technical documentation published by CIRAD Tropix, Sepetir delivers solid mechanical properties and stable drying behavior, but its natural oily exudations present specific preparation challenges when casting with polymer resins.
Wood Appearance, Weight, and Monnin Hardness
Sepetir heartwood ranges from light brown to golden brown depending on the exact botanical species, frequently carrying a pink tinge that darkens upon light exposure. Slabs often exhibit distinctive black stripes, an aromatic scent, and a fine texture. The grain runs straight or slightly interlocked. The sapwood is clearly demarcated from the heartwood, displaying a whitish-grey to light brown or beige-pink tone across a substantial thickness of 7 to 20 cm.
At 12% moisture content, Sepetir has a specific gravity of 0.64. In shop terms, this corresponds to an average density of about 40.0 lb/ft³, meaning a surfaced 2-inch-thick slab weighs approximately 6.7 lb per sq ft. This medium-heavy density offers solid heft for large dining tables or conference desks without becoming unmanageable during assembly.
On the French Monnin hardness scale, Sepetir registers an average rating of 5.4 at 12% moisture content. The Monnin scale measures wood surface resistance, where higher numbers indicate a harder timber (it is not a Janka scale rating and should never be read as one). A score of 5.4 signifies a moderately hard wood capable of resisting daily tabletop impact, supported by a crushing strength of 56 MPa (about 8,120 psi), a static bending strength of 82 MPa (about 11,890 psi), and a modulus of elasticity of 16,900 MPa (about 2,451,000 psi).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Pseudosindora palustris, Copaifera palustris (synonymous), Sindora leiocarpa, Sindora siamensis, Sindora sumatrana, Sindora velutina, Sindora p.p. | |
| Colour / texture / grain | Light brown; texture fine; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.64 | about 40.0 lb/ft³; a 2-inch-thick slab weighs about 6.7 lb per sq ft |
| Monnin hardness (12% MC) | 5.4 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 7.5 % | green to oven-dry |
| Total radial shrinkage | 3.5 % | green to oven-dry |
| Ratio St/Sr | 2.1 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.39 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 26 % | |
| Thermal conductivity | 0.22 W/(m·K) | |
| Crushing strength (12% MC) | 56 MPa | about 8,120 psi |
| Static bending strength (12% MC) | 82 MPa | about 11,890 psi |
| Modulus of elasticity (12% MC) | 16,900 MPa | about 2,451,000 psi |
| Decay (fungi) resistance | Durability class 2 – durable | |
| Termite resistance | Class S – susceptible | |
| Dry-wood borer resistance | Class S – susceptible (risk in all the wood) | |
| Heartwood treatability | Class 3 – poorly permeable | |
| Use class from natural durability | Class 3 – not in ground contact, outside | |
| Drying | rate normal; distortion: no risk or very slight risk; checking: slight risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 53–62 °C | about 127–144 °F |
| Machining | blunting fairly high; saw teeth: stellite-tipped; cutting tools: tungsten carbide | |
| Nailing and screwing | Good but pre-boring necessary | |
| 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, Stability, and Epoxy River Integration
When embedding timber alongside rigid cured epoxy, dimensional movement dictates long-term joint integrity. Sepetir exhibits a total tangential shrinkage of 7.5% and a total radial shrinkage of 3.5%, yielding a tangential-to-radial shrinkage ratio (St/Sr) of 2.1. Its coefficient of volumetric shrinkage is 0.39% per 1% change in moisture content, with a fiber saturation point of 26%.
An St/Sr ratio of 2.1 indicates a moderate tendency toward cupping if moisture fluctuations occur after fabrication. Combined with a 0.39% volumetric change per moisture percentage point, Sepetir slabs must be brought to indoor equilibrium before pouring the epoxy river. Because the cured resin matrix does not expand or contract with humidity, failure to equalize moisture can exert stress along the epoxy-wood bond line.
Natural Durability, Tool Wear, and Fastening
CIRAD classifies the heartwood of Sepetir as Durability Class 2 (durable against xylophagous fungi) and assigns it to Use Class 3 for exterior use not in ground contact. However, the wood is rated Class S (susceptible) to termites and dry-wood borers across all the wood. Heartwood treatability is Class 3 (poorly permeable).
In the machine room, Sepetir exerts a fairly high blunting effect on cutters due to its natural resin content. Stellite-tipped saw teeth and tungsten carbide cutting tools are strongly recommended to maintain clean cuts and prevent burning. For joinery and base mounting, screw-holding is good, though pre-boring is strictly necessary to prevent splitting.
Pros and Cons of Sepetir in Epoxy Tabletops
Pros
- Attractive light brown to golden-brown color with striking black stripes and fine texture.
- No listed CITES trade restrictions under the Washington Convention (2025).
- Good log diameters of 50 to 100 cm yield workable wide boards and live-edge slabs.
- Very low risk of distortion during drying, with no known risks of casehardening or cellular collapse.
- Proven track record in high-class cabinetwork, interior joinery, and furniture components.
Cons
- Oily exudations can cause notable finishing difficulties and complicate resin bonding.
- Fairly high tool-dulling effect caused by natural resins in the wood fibers.
- Pre-boring is mandatory for all structural fasteners and mounting plates.
- Heartwood is susceptible to termites and dry-wood borers without appropriate treatment.
- Wide sapwood band (7 to 20 cm) requires inspection if structural durability is required.
Build Notes for Wood and Epoxy Craftsmen
Slab Selection
Logs range from 50 to 100 cm in diameter, providing ample width for continuous river table leaves. Note that the sapwood measures 7 to 20 cm thick; if you plan to keep live edges inside the epoxy river, ensure the sapwood is clean, firm, and fully stabilized.
Drying
Sepetir dries at a normal rate. CIRAD identifies a slight risk of checking, but reports no known specific risk for collapse or casehardening, and distortion carries no risk or very slight risk. Kiln programs typically operate between 53 and 62 °C (about 127 to 144 °F). Verify that the core moisture content is stable before casting.
Machining
Equip jointers, planers, and routers with tungsten carbide tooling. Because internal resins cause rapid dulling, keep feed rates consistent to prevent resin buildup and edge scorching along gluing surfaces.
Sealing and Finishing
CIRAD specifically highlights difficulties with finishing caused by oily exudations. In epoxy builds, these oils can hinder mechanical adhesion along the river mold walls. Thoroughly degrease contact edges before applying a thin barrier seal coat of epoxy. Ensure the seal coat cures fully per the resin manufacturer’s directions before executing the main deep pour.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Because CIRAD Tropix rates Sepetir as Class S (susceptible) to dry-wood borers throughout the timber, examine raw slabs carefully for pinholes or frass before locking the pieces into a tabletop assembly. (Source: CIRAD Tropix 7 technical sheet: Sepetir.)