An Introduction to Grenadillo for Epoxy Builds
Grenadillo, also known as Grenadille d’Afrique (Dalbergia melanoxylon), is an African timber prized for its extraordinary density, fine grain, and deep coloration. Long utilized for high-class cabinetwork and musical instruments, it presents distinct working characteristics for makers building wood and epoxy tabletops. According to the technical sheet published by CIRAD Tropix, understanding the physical properties and seasoning demands of this species is essential before incorporating it into a resin project.
Appearance, Figure, and Slab Sizing
The heartwood of Grenadillo is dark purple-brown with black streaks, often appearing nearly black, and carries a typical scent of rose. Its sapwood is yellowish white, measuring 1 to 2 cm thick, and is clearly demarcated from the dark core. This sharp boundary provides a vivid natural edge profile next to clear, tinted, or opaque epoxy rivers. The timber possesses a fine texture and straight grain, with interlocked grain noted as absent. Typical log diameters range from 30 to 60 cm, meaning wide single-slab dining tables are uncommon; makers typically use Grenadillo as bookmatched boards, accent sections, or custom river layouts.
Weight and Monnin Hardness
Grenadillo is an exceptionally heavy timber. CIRAD Tropix records an average specific gravity of 1.29 at 12% moisture content, which equates to roughly 80.5 lb/ft³. In practical terms, a 2-inch-thick tabletop slab weighs approximately 13.4 lb per square foot. The logs do not float in water.
Its surface resistance is measured at 22.1 on the Monnin hardness scale at 12% moisture content. The Monnin scale is a French testing standard where higher values indicate harder wood; it should not be confused with or converted to a Janka rating. At 22.1, Grenadillo exhibits extreme resistance to indentation, contributing to its durability in service.
Shrinkage, Movement, and River Table Interface
Dimensional movement is a vital consideration when bonding solid wood to rigid epoxy casting resin. Grenadillo exhibits relatively moderate total shrinkage values from green to oven-dry:
- Total tangential shrinkage: 4.8%
- Total radial shrinkage: 2.9%
- Shrinkage ratio (St/Sr): 1.7
- Coefficient of volumetric shrinkage: 0.36% per 1% change in moisture content
- Fibre saturation point: 25%
A shrinkage ratio of 1.7 indicates a low risk of distortion and cupping across the width of flatsawn or quartersawn material. Once seasoned to shop equilibrium, its moderate volumetric shrinkage coefficient helps reduce stress at the epoxy glue line as ambient humidity fluctuates.
Drying Behavior and Checking Risks
Drying Grenadillo requires patience. CIRAD Tropix notes that the drying rate is slow. While distortion, collapse, and casehardening show no known specific risk, there is a high risk of checking. When kiln drying mature stock, recommended temperatures run between 45 °C and 65 °C (about 113 °F to 149 °F). Any drying checks must be carefully identified, cleaned of loose debris, and sealed or stabilized with resin before executing deep pours.
Tooling, Machining, and Assembly
Because of its dense structure, Grenadillo exerts a high blunting effect on edge tools. Stellite-tipped saw teeth and tungsten carbide cutting tools are necessary to achieve clean cuts and avoid overheating cutters. Peeling and slicing are not recommended.
For joinery and hardware attachment, screw holding is good, but pre-boring is strictly necessary to prevent splitting. CIRAD Tropix explicitly notes that due to the timber’s very high specific gravity, gluing must be performed strictly in compliance with good woodworking codes of practice. Surfaces must be freshly planed or sanded and free of surface contamination before applying adhesives or resin seal coats.
Durability, Listed End-Uses, and CITES Status
Grenadillo heartwood offers exceptional natural resistance to biological attack. It is classified as Durability Class 1 (very durable) against wood-decay fungi, Class D (durable) against termites, and Class D against dry-wood borers (with borer risk limited only to sapwood). Preservative treatments are not required for interior or wet environments. Listed traditional end-uses include musical instruments, wind instruments, high-class cabinetwork, sculpture, turned goods, tool handles, and wood-ware—often mirroring the end-uses of ebony.
Regarding trade regulations, the CIRAD Tropix sheet describes this species as not listed in the CITES Appendices, but that note is out of date: Grenadillo (Dalbergia melanoxylon) is covered by the genus-wide CITES Appendix II listing of all Dalbergia species with annotation #15 (since 02.01.2017; Dalbergia nigra is in Appendix I), according to the BfN CITES tree list, status 05.03.2026. Annotation #15 covers all parts and derivatives except leaves, flowers, pollen, fruit and seeds; finished products up to a maximum of 10 kg of wood of the listed species per shipment; and finished musical instruments, parts and accessories. Ask the seller for CITES documentation for any imported Grenadillo slab or lumber. (Corrected 10/30/2026.)
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Dalbergia melanoxylon | |
| Colour / texture / grain | Black; texture fine; grain straight; interlocked grain absent | |
| Specific gravity (12% MC) | 1.29 | about 80.5 lb/ft³; a 2-inch-thick slab weighs about 13.4 lb per sq ft |
| Monnin hardness (12% MC) | 22.1 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 4.8 % | green to oven-dry |
| Total radial shrinkage | 2.9 % | green to oven-dry |
| Ratio St/Sr | 1.7 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.36 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 25 % | |
| Thermal conductivity | 0.40 W/(m·K) | |
| Crushing strength (12% MC) | 72 MPa | about 10,440 psi |
| Static bending strength (12% MC) | 162 MPa | about 23,500 psi |
| Modulus of elasticity (12% MC) | 20,250 MPa | about 2,937,000 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 slow; distortion: no risk or very slight risk; checking: high risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 45–65 °C | about 113–149 °F |
| Machining | blunting high; saw teeth: stellite-tipped; cutting tools: tungsten carbide | |
| Nailing and screwing | Good but pre-boring necessary | |
| CITES status | Listed in CITES Appendix II with annotation #15 (all Dalbergia species since 02.01.2017, except Dalbergia nigra, which is in Appendix I), per the BfN CITES tree list, status 05.03.2026. Annotation #15 covers all parts and derivatives except leaves, flowers, pollen, fruit and seeds; finished products up to a maximum of 10 kg of wood of the listed species per shipment; and finished musical instruments, parts and accessories. (The CIRAD sheet says not listed; that note is out of date.) |
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).
Is Grenadillo a Good Wood for Epoxy Tables?
Grenadillo makes a striking, durable tabletop material if approached with proper technique. Its dark heartwood, stark sapwood contrast, and low distortion risk make it an attractive partner for epoxy pours. However, builders must account for its substantial weight (about 80.5 lb/ft³), high risk of checking during seasoning, demanding tool wear, and the necessity of precise gluing practices to ensure resin adheres reliably to such a dense substrate.
Sources
- CIRAD Tropix 7 technical sheet: Grenadillo / Grenadille d’Afrique
- CIRAD Tropix 7 technical sheets (index)
- German Federal Agency for Nature Conservation (BfN): List of tree species protected under CITES and Regulation (EC) 338/97, status 05.03.2026
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Because CIRAD Tropix classifies Grenadillo heartwood treatability as Class 3-4 (poorly or not permeable), deep epoxy penetration into the pores will be minimal compared to lower-density hardwoods; thorough mechanical surface scuffing is essential to maximize the physical bond profile. (Source: CIRAD Tropix 7 technical sheet: Grenadillo / Grenadille d’Afrique.)