Overview of Tamarindo (Groçai-Rosa) for Epoxy Tabletops
Tamarindo, also recognized by its ATIBT pilot name Groçai-rosa, encompasses Latin American species from the genus Martiodendron, including Martiodendron elatum, Martiodendron excelsum, and Martiodendron parviflorum. Sourced primarily from Brazil, Colombia, Guyana, and Suriname, this timber offers exceptional strength and striking color contrasts. According to the CIRAD Tropix technical sheet, mature timber exhibits an impressive density and a remarkably balanced shrinkage profile, making it a compelling candidate for custom epoxy river tables and high-wear solid tops.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Martiodendron elatum, Martiodendron excelsum, Martiodendron parviflorum, Martiodendron p.p. | |
| Colour / texture / grain | Orange brown; texture medium; grain undulating and sometimes interlocked; interlocked grain more or less pronounced depending on the origin | |
| Specific gravity (12% MC) | 0.90 | about 56.2 lb/ft³; a 2-inch-thick slab weighs about 9.4 lb per sq ft |
| Monnin hardness (12% MC) | 8.0 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 6.4 % | green to oven-dry |
| Total radial shrinkage | 5.8 % | green to oven-dry |
| Ratio St/Sr | 1.1 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.61 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 22 % | |
| Thermal conductivity | 0.29 W/(m·K) | |
| Crushing strength (12% MC) | 80 MPa | about 11,600 psi |
| Static bending strength (12% MC) | 135 MPa | about 19,580 psi |
| Modulus of elasticity (12% MC) | 24,000 MPa | about 3,481,000 psi |
| Decay (fungi) resistance | Durability class 1-2 – very durable to 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 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 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). Notes. * Tamarindo is the common commercial name of this species, Groçai-rosa is its pilot name in the General Nomenclature of Tropical Timber (ATIBT 2016). |
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 Tamarindo look like in a finished tabletop?
Tamarindo heartwood displays an orange brown reference color that ranges from pinkish-brown to reddish-brown, accompanied by visible growth rings. This rich core stands in sharp contrast to the whitish sapwood, which typically measures from 5 to 10 cm in thickness on logs measuring 70 to 90 cm in diameter. The grain is undulating and sometimes interlocked, with the degree of interlocking varying from more or less pronounced depending on the tree’s origin. Paired with a medium texture, this grain figure creates deep, shifting highlights under clear epoxy resin flood coats and penetrating finishes.
How heavy and stiff is a Tamarindo wood slab?
Builders should anticipate a very heavy board. At 12% moisture content, Tamarindo has a specific gravity of 0.90, which translates to a density of about 56.2 lb/ft³. A 2-inch-thick tabletop slab weighs approximately 9.4 lb per sq ft before factoring in the weight of poured epoxy resin. In structural metrics, Tamarindo displays outstanding stiffness and load-bearing power, with a modulus of elasticity of 24,000 MPa (about 3,481,000 psi), a static bending strength of 135 MPa (about 19,580 psi), and a crushing strength of 80 MPa (about 11,600 psi). Heavy table bases and sturdy legs are essential to support these tops.
How hard is Tamarindo, and how is its hardness measured?
Tamarindo has a Monnin hardness rating of 8.0 at 12% moisture content. The Monnin test is a French timber hardness scale based on cylinder indentation where higher values signify a harder surface; it is never converted to Janka hardness. A Monnin value of 8.0 places Tamarindo among very hard hardwoods, indicating that tabletop surfaces will resist everyday dings, scratches, and denting in commercial or busy residential dining settings.
How stable is Tamarindo next to an epoxy river?
Dimensional movement is a vital concern when bonding wood slabs to rigid epoxy resin. Tamarindo performs exceptionally well regarding directional movement balance:
- Total tangential shrinkage: 6.4 %
- Total radial shrinkage: 5.8 %
- Shrinkage ratio (St/Sr): 1.1
- Coefficient of volumetric shrinkage: 0.61 % per % MC
- Fibre saturation point: 22 %
Because the St/Sr ratio is 1.1, Tamarindo has nearly uniform shrinkage across radial and tangential planes. A ratio close to 1 represents minimal cupping tendency across the slab, significantly reducing the shear stress placed on the epoxy-to-wood bond line as indoor humidity fluctuates.
What are the drying characteristics and risks?
CIRAD Tropix data rates the drying rate of Tamarindo as slow. Despite its high density, the timber shows good behavior in the kiln or drying shed: distortion risk is rated as slight, checking risk is slight, and there are no known specific risks for collapse or casehardening. When running a controlled kiln schedule, suggested temperatures range from 53 to 65 °C (about 127 to 149 °F). Slabs must be thoroughly dried to target interior equilibrium before casting, followed by resin manufacturer guidelines for sealing edges.
How does Tamarindo handle tooling and assembly?
Due to the wood’s density and undulating grain, the blunting effect on cutter knives is fairly high. The CIRAD Tropix technical sheet recommends using stellite-tipped saw teeth and tungsten carbide cutting tools to maintain clean edges and avoid burn marks. For joinery and mechanical fasteners, nailing and screwing properties are good, but pre-boring is strictly necessary to prevent splitting. When joining boards or attaching base plates, thorough pilot drilling ensures secure attachment.
What is the durability and CITES status of Tamarindo?
The heartwood provides natural durability class 1-2 (very durable to durable against wood-decay fungi), Class D resistance to dry-wood borers (with risk limited strictly to the sapwood), and Class D resistance to termites. It achieves use class 4 (suitable for contact with the ground or fresh water) and requires no preservative treatment. The heartwood is poorly or not permeable (treatability class 3-4). Tamarindo is not listed in the CITES Appendices (Washington Convention 2025). Its industrial uses include heavy carpentry, flooring, decking, cladding, exterior joinery, and turned goods, confirming its extreme longevity in fine furniture builds.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Because log sapwood measures from 5 to 10 cm thick and CIRAD Tropix notes that dry-wood borer risk is limited to the sapwood, live edge builders retaining the whitish sapwood border should thoroughly inspect edges before sealing and casting. (Source: CIRAD Tropix 7 technical sheet: Tamarindo (Groçai-rosa).)