Padauk Amboina as an Epoxy River Table Wood
Padauk amboina refers to timber from Pterocarpus dalbergioides, Pterocarpus indicus, and its synonym Pterocarpus vidalianus. Originating in Asia-Oceania—including the Andaman Islands, Indonesia, Malaysia, Myanmar, Papua New Guinea, and the Philippines—this member of the Fabaceae family produces exceptionally striking hardwood. According to the timber research published in the CIRAD Tropix technical sheet, mature logs range from 50 to 100 cm in diameter, yielding broad boards and live-edge slabs ideal for statement furniture.
Visually, Padauk amboina is celebrated for its deep coloration and rich figure. The sapwood is pale straw, measuring 2 to 5 cm thick, and clearly demarcated from the heartwood. The heartwood ranges from deep blood-red with almost black markings to honey-colored with reddish-black figure, naturally darkening to a lustrous dark brown over time. It carries a noticeable rose scent and coarse texture, with grain that is straight or distinctly interlocked. Highly prized amboina burrs feature wavy parenchyma structures and intricate dark patterning that make extraordinary focal points when cast into liquid resin.
Density, Hardness, and Structural Strength
At 12% moisture content, Padauk amboina exhibits an average specific gravity of 0.70. For a tabletop builder, this corresponds to an approximate air-dry density of 43.7 lb/ft³, or about 7.3 lb per square foot for a standard 2-inch-thick tabletop slab. This gives dining tables, desks, and consoles substantial physical presence without reaching the excessive weights of ultra-dense tropical woods.
In standard European testing, timber hardness is frequently measured using the Monnin hardness test—a French indentation scale where higher numbers reflect greater surface hardness, distinct from the American Janka test. While the CIRAD Tropix data sheet does not publish a specific Monnin figure for this species, it highlights the wood’s high natural hardness. Structurally, the wood exhibits strong load resistance with a crushing strength of 51 MPa (about 7,400 psi), a static bending strength (MOR) of 82 MPa (about 11,890 psi), and a modulus of elasticity (MOE) of 16,600 MPa (about 2,408,000 psi). Slabs possess exceptional stiffness across long unsupported spans.
Shrinkage and Stability Along the River Joint
Dimensional movement is the primary consideration when bonding solid timber to a rigid cured resin channel. Severe seasonal movement can stress epoxy joints, leading to edge lifting or shear cracks along the interface. Padauk amboina performs remarkably well in this environment due to its low total shrinkage values.
CIRAD Tropix records a total tangential shrinkage of 4.0% and a total radial shrinkage of 2.8% from green to oven-dry moisture conditions. Furthermore, the ratio of tangential to radial shrinkage (St/Sr) is exceptionally low at 1.4. A ratio close to 1 indicates uniform movement in both directions across the board, which minimizes cupping, warping, and seasonal distortion adjacent to the epoxy river. Its thermal conductivity is listed at 0.23 W/(m·K).
Drying Behavior and Defect Risks
Preparing slabs for epoxy casting demands thorough drying to equalize internal stresses. The drying rate for Padauk amboina is classified as normal to slow. Importantly, CIRAD evaluations report no risk or very slight risk of distortion, as well as no risk or very slight risk of surface checking. There is also no known specific risk of internal collapse or casehardening during drying.
For operations employing controlled kilns, CIRAD suggests drying schedules running between 53 °C and 65 °C (about 127 °F to 149 °F) as the moisture content steps downward from above 50% to final shop-ready levels.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Pterocarpus dalbergioides, Pterocarpus indicus, Pterocarpus vidalianus (synonymous) | |
| Colour / texture / grain | Light red; texture coarse; grain straight or interlocked; interlocked grain marked | |
| Specific gravity (12% MC) | 0.70 | about 43.7 lb/ft³; a 2-inch-thick slab weighs about 7.3 lb per sq ft |
| Total tangential shrinkage | 4.0 % | green to oven-dry |
| Total radial shrinkage | 2.8 % | green to oven-dry |
| Ratio St/Sr | 1.4 | closer to 1 = less cupping tendency |
| Thermal conductivity | 0.23 W/(m·K) | |
| Crushing strength (12% MC) | 51 MPa | about 7,400 psi |
| Static bending strength (12% MC) | 82 MPa | about 11,890 psi |
| Modulus of elasticity (12% MC) | 16,600 MPa | about 2,408,000 psi |
| Decay (fungi) resistance | Durability class 1 – very durable | |
| Termite resistance | Class D – durable | |
| Dry-wood borer resistance | Class D – durable (sapwood demarcated, risk limited | |
| Heartwood treatability | Class 3-4 – poorly or not permeable | |
| Use class from natural durability | Class 4 – in ground or fresh water contact | |
| Drying | rate normal to slow; 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 | 53–65 °C | about 127–149 °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).
Tooling, Machining, and Assembly in the Shop
While Padauk amboina planes and shapes cleanly, it exerts a fairly high blunting effect on cutting edges. CIRAD notes that this dulling effect is caused by natural latex- and resin-like deposits within the pores. To preserve edge geometry when flattening large glued slabs, woodworkers should employ tungsten carbide tooling and stellite-tipped saw teeth. Slicing and peeling properties are rated as good.
For mechanical fastening, such as attaching structural table bases or steel C-channels into the underside, screw-holding is rated as good, though pre-boring is strictly necessary to prevent splitting near edges. Heartwood treatability falls into Class 3–4 (poorly or not permeable), meaning the wood does not absorb chemical preservatives readily, making proper mechanical surface prep essential before applying primer seals and resin pours.
Durability and Conservation Status
Padauk amboina heartwood offers supreme natural resilience. CIRAD rates it in Durability Class 1 (very durable) against wood-decay fungi, alongside Class D (durable) ratings against termites and dry-wood borers (with borer risk limited to the demarcated sapwood). It meets Class 4 natural durability (suitable for ground contact or freshwater exposure), and CIRAD notes that due to its hardness, it naturally covers use Class 5 exposure (permanently or regularly submerged in salt water).
Regarding conservation regulations, this species is not listed in the CITES Appendices (Washington Convention 2025). Traditional end-uses include high-class cabinetwork, musical instruments, turned goods, indoor staircases, flooring, ship building, exterior panelling, and sliced veneer.
Is Padauk Amboina a Good Epoxy Table Wood?
Padauk amboina is an outstanding species for custom epoxy river tables and high-end tabletops. Its total tangential shrinkage of only 4.0% and a St/Sr ratio of 1.4 place it among the most dimensionally stable tropical hardwoods available, ensuring that cured epoxy seams remain stable through seasonal humidity shifts. Combined with minimal drying risks, rich red-to-honey heartwood, and dramatic burr figure, it delivers exceptional structural and aesthetic performance for custom river table construction.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Because CIRAD identifies internal latex- and resin-like deposits as the primary cause of tool dulling in Padauk amboina, always wipe the machined slab surfaces thoroughly before sealing to ensure these natural deposits do not interfere with raw resin adhesion. (Source: CIRAD Tropix 7 technical sheet: Padauk amboina.)