Melunak Characteristics and Slab Sizing
Melunak refers to timber derived from species within the genus Pentace, including Pentace burmanica, Pentace triptera, and other related Pentace species native to Asia-Oceania. Documented extensively by the CIRAD Tropix technical sheet, Melunak produces logs with diameters ranging from 60 to 90 cm. This allows table builders to source mid-width live-edge slabs or straight-edged boards suitable for custom wood and epoxy river tabletops.
Visually, Melunak displays a red brown tone. Its heartwood presents as gold red brown that turns darker when exposed to light, while the sapwood is not clearly demarcated and varies from straw-coloured to pale reddish brown depending on species and geographic origin. Slabs often exhibit slight interlocked grain with a medium texture, showing fine silver figure, transverse stripes, zig-zag runs of parenchyma, and moiré patterning on radial faces. The wood is noted as a possible substitute for Mahogany, but the CIRAD Tropix data emphasizes that it needs filling before polishing due to its texture.
Weight, Mechanical Strength, and Monnin Hardness
Melunak has an average specific gravity of 0.62 at 12% moisture content. In working shop terms, this corresponds to a density of about 38.7 lb/ft³, meaning a 2-inch-thick slab weighs approximately 6.5 lb per sq ft. This medium weight provides solid heft for large dining tables or desks without becoming overly cumbersome during shop handling and mold assembly.
Mechanically, mature Melunak wood exhibits a crushing strength of 63 MPa (about 9,140 psi), static bending strength of 111 MPa (about 16,100 psi), and a modulus of elasticity of 18,700 MPa (about 2,712,000 psi). Its surface resistance is evaluated using the French Monnin hardness scale, where it measures 3.1 at 12% moisture content. The Monnin scale is an indentation metric where higher numbers denote harder wood, and it should never be converted to the American Janka scale. A rating of 3.1 indicates moderate surface firmness adequate for interior furniture, though proper epoxy edge bonding and flood or seal coats help protect working surfaces from contact wear.
Movement, Drying Hazards, and Epoxy Interface Stability
When incorporating wood slabs alongside cast resin, wood movement across changing ambient humidity is a key engineering consideration. Melunak features a total tangential shrinkage (St) of 8.3% and a total radial shrinkage (Sr) of 5.5% from green to oven-dry, resulting in an St/Sr ratio of 1.5. Combined with a volumetric shrinkage coefficient of 0.45% per 1% change in moisture content and a fibre saturation point of 25%, the timber shows moderate movement properties.
The primary hazard when preparing Melunak for epoxy integration lies in its drying behavior. The CIRAD Tropix sheet reports a slow drying rate with only a slight risk of distortion, but a high risk of checking. Deep checks or end splits can compromise the structural boundary between the wood and the cured epoxy resin. Slabs subjected to artificial drying must follow gradual schedules, such as suggested kiln temperatures between 53 and 62 °C (about 127 to 144 °F), to minimize stress fractures before sealing.
Machining, Fastening, and Durability
Melunak machines cleanly using standard tooling. Its blunting effect on cutters is rated as normal, allowing the use of ordinary cutting tools and ordinary or alloy steel sawteeth. Slicing and peeling are both rated good. For table base mounting, the timber provides good nailing and screwing holding capacity. However, because heartwood treatability is Class 3-4 (poorly or not permeable), any deep penetration of topical chemical preservatives into solid heartwood is limited.
Regarding natural durability, Melunak heartwood is classified as Durability class 3 (moderately durable) against xylophagous fungi, but Class S (susceptible) to termites and dry-wood borers across all the wood. These characteristics dictate an assigned natural durability rating of Class 2, restricting use to indoor environments or under cover where dampness is possible. CIRAD explicitly notes that Melunak is not recommended for temporary or permanent humidification, aligning with its common end-uses such as current furniture, flooring, interior joinery, interior panelling, and indoor staircases.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Pentace burmanica, Pentace triptera, Pentace p.p. | |
| Colour / texture / grain | Red brown; texture medium; grain interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.62 | about 38.7 lb/ft³; a 2-inch-thick slab weighs about 6.5 lb per sq ft |
| Monnin hardness (12% MC) | 3.1 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 8.3 % | green to oven-dry |
| Total radial shrinkage | 5.5 % | green to oven-dry |
| Ratio St/Sr | 1.5 | 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 | 25 % | |
| Thermal conductivity | 0.21 W/(m·K) | |
| Crushing strength (12% MC) | 63 MPa | about 9,140 psi |
| Static bending strength (12% MC) | 111 MPa | about 16,100 psi |
| Modulus of elasticity (12% MC) | 18,700 MPa | about 2,712,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class S – susceptible | |
| 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 2 – inside or under cover (dampness possible) | |
| Drying | rate slow; distortion: slight risk; checking: high risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 53–62 °C | about 127–144 °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).
Pre-Pour Checklist for Melunak Epoxy Tabletops
- Inspect for log width and sapwood boundaries: Verify slab width relative to the typical 60 to 90 cm log diameter, accounting for the 4 to 8 cm sapwood thickness that may blend gradually into the gold red brown heartwood.
- Examine thoroughly for drying checks: Because Melunak carries a high risk of checking during slow drying, probe all surface checks, end splits, and grain fissures before casting.
- Pre-fill open grain and voids: Following CIRAD notes that the species needs filling before polishing, seal the medium-textured pores, parenchyma runs, and any checks with a thin seal coat to prevent trapped air bubbles during the deep pour.
- Confirm CITES regulatory compliance: Check procurement paperwork against the Washington Convention (2025), which confirms this species is not listed in the CITES Appendices.
- Plan indoor-only furniture placement: Adhere to Class 2 indoor parameters, keeping the finished epoxy table out of exterior or permanently humid environments where fungal and insect risks increase.
- Prepare mechanical fasteners: Take advantage of good screwing properties by installing threaded inserts or mechanical fasteners into pre-drilled holes to secure table legs without splitting.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: CIRAD Tropix warns that Melunak is Class S (susceptible) to dry-wood borers with risk present in all the wood, meaning raw slabs should be closely inspected for active boreholes and treated with an appropriate preservative before pouring resin over them. (Source: CIRAD Tropix 7 technical sheet: Melunak.)