Tatajuba as a River Table Wood
Tatajuba (botanical names Bagassa guianensis and its synonym Bagassa tiliifolia, also known in the trade as Bagasse) is a dense Latin American hardwood originating from countries such as Brazil, French Guiana, Guyana, and Suriname. While frequently specified for heavy carpentry, exterior decking, and marine hydraulic works, it is also listed for cabinetwork and high-class furniture. When sourced for custom epoxy river tables and hybrid tabletops, its physical weight, interlocked grain, and moisture response require specific shop considerations documented in the CIRAD Tropix technical sheet.
Color, Figure, and Density
Commercial logs typically range from 50 to 90 cm in diameter with a sapwood band between 2 and 4 cm thick. The sapwood is clearly demarcated from the heartwood. Freshly cut heartwood displays a vibrant yellow tone, which oxidizes over time into a yellow-brown to dark brown patina. The wood has a medium texture and a marked interlocked grain pattern.
Tatajuba is heavy. At 12% moisture content, it has an average specific gravity of 0.80, which translates to a density of roughly 49.9 lb/ft³. A surfaced 2-inch-thick tabletop slab weighs approximately 8.3 lb per square foot before resin is added. Table bases and bracing must be designed to carry this substantial dead weight.
Hardness and Mechanical Properties
The CIRAD Tropix technical sheet rates Tatajuba with a Monnin hardness of 6.4 at 12% moisture content. The Monnin hardness test is a standardized French scale based on cylinder indentation where a higher value represents a harder surface (it is distinct from and must never be converted to the Janka scale). For comparison across table applications, a rating of 6.4 indicates a very firm, dent-resistant working surface.
Mechanically, Tatajuba demonstrates exceptional stiffness and bending performance at 12% moisture content:
- Crushing strength: 78 MPa (about 11,310 psi)
- Static bending strength (MOR): 109 MPa (about 15,810 psi)
- Modulus of elasticity (MOE): 21,490 MPa (about 3,117,000 psi)
Shrinkage, Stability, and the Epoxy River Interface
Understanding wood movement is essential when locking timber to a rigid cured polymer river. Tatajuba exhibits a total tangential shrinkage of 5.2% and a total radial shrinkage of 3.7% from green to oven-dry, producing a tangential-to-radial (St/Sr) ratio of 1.4. Its fibre saturation point is 20%, and its coefficient of volumetric shrinkage is 0.53% per 1% change in moisture content.
Although the 1.4 ratio suggests a moderate resistance to cupping, CIRAD Tropix references standard NF B 54-040 noting that Tatajuba wood is classified as not very stable. The marked interlocked grain introduces significant internal stresses. During the drying process, there is a normal to slow drying rate with a slight risk of checking, but a high risk of distortion. When incorporated into an epoxy tabletop, unchecked moisture shifts can apply uneven lateral shear stresses along the epoxy bond line.
Machining, Tool Wear, and Bonding Considerations
Tatajuba contains silica, naturally covering European use class 5 (marine submersion). Consequently, tool blunting is fairly high. CIRAD Tropix advises using stellite-tipped saw teeth and tungsten carbide cutting edges when milling, jointing, or flattening slabs. Marked interlocked grain may also cause tearout or prove troublesome during surface planing.
For joinery and mechanical fasteners, pre-boring is mandatory despite good overall screw-holding properties. When gluing Tatajuba, CIRAD Tropix cautions that due to the species’ high specific gravity, gluing must be performed strictly in compliance with professional codes of practice. Surfaces flanking the river channel must be freshly prepared, flat, free of milling dust, and wiped clean before pouring seal coats or deep casting resin.
Durability and International Trade Status
Tatajuba is inherently resistant to biological degradation. It achieves Durability Class 1 (very durable) against wood-decay fungi, Class D (durable) against termites, and Class D against dry-wood borers (with risks limited strictly to the sapwood). The heartwood is poorly permeable (treatability Class 3). Regarding regulatory and conservation status, Tatajuba is not listed in the CITES Appendices (Washington Convention 2025).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Bagassa guianensis, Bagassa tiliifolia (synonymous) | |
| Other trade names | Bagasse | |
| Colour / texture / grain | Yellow brown; texture medium; grain interlocked; interlocked grain marked | |
| Specific gravity (12% MC) | 0.80 | about 49.9 lb/ft³; a 2-inch-thick slab weighs about 8.3 lb per sq ft |
| Monnin hardness (12% MC) | 6.4 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 5.2 % | green to oven-dry |
| Total radial shrinkage | 3.7 % | green to oven-dry |
| Ratio St/Sr | 1.4 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.53 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 20 % | |
| Thermal conductivity | 0.26 W/(m·K) | |
| Crushing strength (12% MC) | 78 MPa | about 11,310 psi |
| Static bending strength (12% MC) | 109 MPa | about 15,810 psi |
| Modulus of elasticity (12% MC) | 21,490 MPa | about 3,117,000 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 – poorly permeable | |
| Use class from natural durability | Class 4 – in ground or fresh water contact | |
| Drying | rate normal to slow; distortion: high 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 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).
Practical Pre-Pour Checklist for Tatajuba Slabs
- Confirm Equilibrium Moisture Content: Ensure the timber is dried to interior equilibrium moisture content (kiln schedules operate between 53 °C and 65 °C, or roughly 127 °F to 149 °F) to reduce high distortion risks before bonding.
- Inspect for Internal Stresses: Examine the board faces for twist, bow, or wind caused by the marked interlocked grain before machining river profiles.
- Freshen Cutting Edges: Use sharp tungsten carbide cutters to machine the live edge or river walls, minimizing burnishing and fiber tearing caused by the wood’s silica content.
- Relieve Planing Glaze: Scuff-sand the resin contact edges to open the dense, 0.80 specific gravity face for mechanical adhesion.
- Equip Respiratory Protection: Run active dust collection and wear appropriate shop dust protection, as Tatajuba sawdust is documented as sometimes irritant.
- Pre-Seal the River Edges: Apply a thorough epoxy seal coat along the live edges to prevent outgassing bubbles from entering the main deep-pour channel.
- Pre-Bore Base Mounts: Drill pilot holes for all threaded inserts or mounting fasteners underneath the finished top to prevent splitting dense wood grain.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: During the drying phase, monitor stacking carefully because spacer sticks can stain Tatajuba wood, and ensure shop air filtration handles the sawdust, which CIRAD Tropix identifies as sometimes irritant. (Source: CIRAD Tropix 7 technical sheet: Tatajuba.)