Kauri in Wood and Epoxy Builds
Kauri (Agathis p.p.) is a prominent softwood belonging to the Araucariaceae family, sourced across Asia-Oceania from regions such as Australia, Malaysia, Indonesia, Papua New Guinea, and New Caledonia. Documented extensively by the French research institute CIRAD Tropix, Kauri has a long history in architectural millwork and fine woodworking. When adapted to modern epoxy river tables and wood/epoxy tabletops, its physical traits require a clear understanding of its density, movement, and shop workability.
Appearance, Figure, and Grain
Kauri logs, which commonly range from 60 to 120 cm in diameter, produce boards with a fine, uniform texture and predominantly straight grain. Interlocked grain is absent. The wood presents a light yellow or cream white baseline, frequently displaying pink reflections. Over time and with exposure to light, the surface matures into a warm golden brown. Quarter-sawn cuts often showcase an appealing moiré effect, and planed surfaces exhibit a natural luster. CIRAD notes that in overall appearance, Kauri can resemble cherry wood (Cerasus avium). The sapwood measures between 8 and 11 cm thick and is not clearly demarcated from the heartwood.
Weight, Hardness, and Mechanical Strength
At 12% moisture content, mature Kauri has an average specific gravity of 0.53, translating to an average air-dry density of approximately 33.1 lb/ft³. For table builders planning slab support, a 2-inch-thick tabletop blank weighs about 5.5 lb per square foot before resin is poured.
Hardness is measured on the Monnin scale at 2.5. The Monnin test is a standard French hardness scale where a higher value signifies harder wood; it is not directly convertible to the American Janka scale. A rating of 2.5 places Kauri in a moderate-to-soft category, requiring sensible care against heavy impacts in furniture applications. Its structural stiffness and strength are dependable, with a modulus of elasticity of 11,240 MPa (about 1,630,000 psi), static bending strength of 76 MPa (about 11,020 psi), and crushing strength of 43 MPa (about 6,240 psi).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Agathis p.p. | |
| Colour / texture / grain | Light yellow; texture fine; grain straight; interlocked grain absent | |
| Specific gravity (12% MC) | 0.53 | about 33.1 lb/ft³; a 2-inch-thick slab weighs about 5.5 lb per sq ft |
| Monnin hardness (12% MC) | 2.5 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 5.9 % | green to oven-dry |
| Total radial shrinkage | 4.0 % | green to oven-dry |
| Ratio St/Sr | 1.5 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.41 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 30 % | |
| Thermal conductivity | 0.18 W/(m·K) | |
| Crushing strength (12% MC) | 43 MPa | about 6,240 psi |
| Static bending strength (12% MC) | 76 MPa | about 11,020 psi |
| Modulus of elasticity (12% MC) | 11,240 MPa | about 1,630,000 psi |
| Decay (fungi) resistance | Durability class 3 to 4 – moderately to poorly durable | |
| Termite resistance | Class S – susceptible | |
| Dry-wood borer resistance | Class S – susceptible (risk in all the wood) | |
| Heartwood treatability | Class 2 – moderately permeable | |
| Use class from natural durability | Class 1 – inside (no dampness) | |
| Drying | rate normal to slow; distortion: slight risk; checking: 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 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).
Shrinkage, Wood Movement, and the Epoxy River Interface
Dimensional movement is the primary consideration when locking natural slabs into a rigid epoxy pour. Kauri exhibits a total tangential shrinkage of 5.9% and a total radial shrinkage of 4.0%, yielding an St/Sr ratio of 1.5. A shrinkage ratio near 1.5 indicates a low tendency toward cupping or warping during environmental moisture shifts.
Its coefficient of volumetric shrinkage is 0.41% per 1% change in moisture content, with a fiber saturation point of 30%. Because epoxy resin cures into a solid, unyielding casting, any subsequent swelling or shrinking in adjacent wood creates shear stress along the joint. Kauri’s moderate shrinkage values mean that if lumber is fully acclimatized before fabrication, the risk of perimeter pulling or joint failure remains minimal.
Drying Behavior and Tooling
Kauri dries at a normal to slow pace. CIRAD records only a slight risk of distortion and a slight risk of checking, with no known specific risk of collapse or casehardening. However, raw material carries a notable risk of blue stain during the drying cycle. Suggested kiln schedules operate between 53 and 65 °C (about 127 to 149 °F).
In the shop, Kauri is exceptionally cooperative:
- Tool wear: Blunting effect on cutting edges is normal. Ordinary cutting tools and standard steel or alloy steel saw blades work effectively.
- Surfacing: Planed surfaces finish exceptionally smooth and lustrous.
- Joinery: Nailing and screwing properties are rated as good.
- Finishing: CIRAD notes the wood stains well, making it adaptable to varied topcoat styles.
Durability, Environmental Status, and Listed Uses
Natural heartwood durability against fungi falls into class 3 to 4 (moderately to poorly durable). The wood is classified as susceptible (Class S) to dry-wood borers and termites. As a result, its natural durability dictates a Use Class 1 rating, strictly limiting finished pieces to interior environments free from dampness. The heartwood is moderately permeable (Class 2), showing moderate to good amenability to preservative treatment if required.
Kauri is not listed in the CITES Appendices (Washington Convention 2025). CIRAD documents its common end-uses in cabinetwork for high-class furniture, current furniture components, interior joinery, interior panelling, glued laminated stock, turned goods, and cooperage.
Is Kauri a Good Epoxy Table Wood?
Kauri is an excellent, well-behaved candidate for interior epoxy river tables. Its straight grain, lack of interlocked fibers, and balanced St/Sr ratio of 1.5 provide steady dimensional stability next to cured resin. While its Monnin hardness of 2.5 means it is not scratch-proof against aggressive wear, its lustrous planed face, light golden tones, and pleasant moiré figure yield a clean, elegant aesthetic for dining and conference tops.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Because Kauri heartwood and sapwood are both prone to blue stain fungi during early drying, inspect all raw board edges thoroughly before sealing; any residual fungal discoloration can darken under a clear epoxy flood coat. (Source: CIRAD Tropix 7 technical sheet: Kauri.)