Mersawa Wood for Epoxy River Tables
Mersawa (derived from species in the genus Anisoptera, such as Anisoptera costata, Anisoptera curtisii, and Anisoptera thurifera, among others) is a tropical hardwood native to Asia-Oceania. Also traded under names like Krabak, Bella rosa, and Ven-ven, it offers builders wide dimensional stock and a distinct warm appearance. However, integrating this timber into resin projects requires understanding its specific density, shrinkage rates, and blunting characteristics as detailed in the CIRAD Tropix technical sheet.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Anisoptera costata, Anisoptera cochinchinensis (synonymous), Anisoptera curtisii, Anisoptera glabra, Anisoptera laevis, Anisoptera marginata, Anisoptera scaphula, Anisoptera thurifera, Anisoptera p.p. | |
| Other trade names | Bella rosa, Krabak, Ven-ven | |
| Colour / texture / grain | Orange yellow; texture coarse; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.63 | about 39.3 lb/ft³; a 2-inch-thick slab weighs about 6.6 lb per sq ft |
| Monnin hardness (12% MC) | 2.6 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 8.8 % | green to oven-dry |
| Total radial shrinkage | 3.7 % | green to oven-dry |
| Ratio St/Sr | 2.4 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.52 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 32 % | |
| Thermal conductivity | 0.21 W/(m·K) | |
| Crushing strength (12% MC) | 46 MPa | about 6,670 psi |
| Static bending strength (12% MC) | 83 MPa | about 12,040 psi |
| Modulus of elasticity (12% MC) | 12,930 MPa | about 1,875,000 psi |
| Decay (fungi) resistance | Durability class 4 – poorly durable | |
| Termite resistance | Class M – moderately durable | |
| Dry-wood borer resistance | Class S – susceptible (risk in all the wood) | |
| Heartwood treatability | Class 3-4 – poorly or not permeable | |
| Use class from natural durability | Class 1 – inside (no dampness) | |
| Drying | rate slow; distortion: 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 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).
What does Mersawa look like, and how wide are the slabs?
Mersawa displays an orange-yellow heartwood that can sometimes darken over time to a rich golden brown. The wood features a coarse texture with grain that is either straight or slightly interlocked. A defining visual characteristic is the presence of whitish resin veins coursing through the grain. Sapwood measures between 5 and 8 cm thick and is not clearly demarcated from the heartwood.
For makers building wide river dining tables or expansive conference desks, Mersawa logs provide significant width potential. According to CIRAD, mature logs range from 60 to 150 cm in diameter (roughly 24 to 59 inches), making it possible to source wide live-edge slabs or bookmatched sets without excessive panel glue-ups.
How heavy and hard is Mersawa for a custom tabletop?
At 12% moisture content, Mersawa has an average specific gravity of 0.63, which translates to a density of approximately 39.3 lb/ft³. For shop handling, a standard 2-inch-thick tabletop slab weighs roughly 6.6 pounds per square foot. This places it in a moderate weight class—substantial enough to feel high-end without being prohibitively heavy.
The wood has an average Monnin hardness rating of 2.6. Monnin hardness is a French measurement scale where higher values indicate harder timber (it is not equivalent to a Janka rating). CIRAD Tropix notes that Mersawa’s hardness varies from soft to fairly hard, accompanied by a crushing strength of 46 MPa (around 6,670 psi) and a modulus of elasticity of 12,930 MPa. For tabletop use, it offers solid functional resistance for daily furniture applications.
How stable is Mersawa next to an epoxy river?
Dimensional movement is the primary consideration when pairing timber with rigid epoxy resin. Mersawa exhibits a total tangential shrinkage of 8.8% and a total radial shrinkage of 3.7%, yielding an St/Sr ratio of 2.4. Its coefficient of volumetric shrinkage is 0.52% per 1% change in moisture content, with a fiber saturation point at 32%.
Because the tangential-to-radial ratio is 2.4, flatsawn boards have a moderate tendency toward cupping compared to quartersawn material. Furthermore, a volumetric coefficient of 0.52% means the wood will expand and contract moderately if indoor relative humidity shifts. Builders should seal all surfaces evenly and secure tabletops with slotted tabletop fasteners to allow natural movement without straining the wood-to-epoxy bond line.
What drying challenges and risks should builders expect?
CIRAD Tropix classifies the drying rate of Mersawa as slow. Fortunately, the structural drying risks are low: there is only a slight risk of distortion and a slight risk of surface checking. Casehardening and cell collapse have no known specific risks. Recommended kiln drying schedules specify temperatures between 53 °C and 62 °C (approximately 127 °F to 144 °F).
A critical detail highlighted by CIRAD is the occasional presence of internal water pockets. Slabs must be brought down to a stable, uniform moisture content throughout their entire thickness before epoxy casting. Any wet pockets trapped beneath deep-pour epoxy can compromise curing or lead to delamination over time.
How does Mersawa machine, and will it dull shop tooling?
Working Mersawa requires heavy-duty cutters. The CIRAD Tropix technical sheet reports that the blunting effect on tools is high. The use of stellite-tipped saw blades and tungsten carbide cutting knives is specifically recommended to avoid rapid dulling and burning.
While peeling and slicing properties are rated good, woodworkers should note that quartersawn faces show a tendency to tear during planing, especially where the grain is interlocked. Taking light passes and keeping carbide cutters sharp helps maintain crisp edges along the epoxy river channel.
What are the best practices for assembling, filling, and finishing?
Mersawa receives a good rating for nailing and screwing, making it straightforward to mount onto table bases and structural stretchers (pre-drilling remains good shop practice). Because of its coarse texture and resin veins, CIRAD Tropix explicitly recommends grain filling to achieve a smooth, high-quality finish.
The species is recognized in industry for glued laminated construction, interior joinery, furniture, and sliced veneer. For epoxy projects, woodworkers should follow standard resin manufacturer protocols: thoroughly degrease surfaces, clear out loose debris along the live edge, apply a thin seal coat to prevent outgassing from the coarse pores, and allow the seal coat to cure before proceeding with the main river pour.
Is Mersawa suitable for outdoor epoxy tables, and what is its CITES status?
Mersawa is strictly intended for indoor use. CIRAD rates its heartwood as Durability Class 4 (poorly durable against wood-decay fungi), Class S for dry-wood borers (susceptible throughout the wood), and Class M for termites (moderately durable). Its natural durability corresponds to Use Class 1: interior installations without dampness. Preservative treatment is required against borers, but its heartwood treatability is Class 3-4 (poorly or not permeable). CIRAD explicitly states that use is not recommended under temporary or permanent humidification.
Regarding trade regulations, Mersawa is not listed in the CITES Appendices (Washington Convention 2025), making it legally importable and documented under standard timber trade practices.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: CIRAD Tropix notes that Mersawa is prone to resin exudation when subjected to steaming; builders should be vigilant about inspecting live edges for active resin bleed, as localized resin pockets can inhibit epoxy adhesion if not cleaned before sealing. (Source: CIRAD Tropix 7 technical sheet: Mersawa.)