Guariuba Wood for Epoxy River Tables
Guariuba (Clarisia racemosa) is a Latin American hardwood documented in the CIRAD Tropix technical sheet. In high-end epoxy woodworking, it provides a distinctive tone and dependable physical substance. The timber is yellow when freshly worked, maturing into a lustrous brown under light exposure. Flat-sawn stock presents straight or occasionally marked interlocked grain with a medium texture, whereas quartersawn cuts showcase an attractive ribbon-like figure. Its sapwood is clearly demarcated from the heartwood, measuring from 2 to 5 cm in thickness.
With an average specific gravity of 0.69 at 12% moisture content, Guariuba weighs roughly 43.1 lb/ft³, meaning a 2-inch-thick slab averages about 7.2 lb per square foot. Hardness is evaluated on the French Monnin scale at 4.6—a metric where higher values denote greater hardness, which must not be confused with or converted to Janka values. Mechanically, Guariuba delivers strong load-bearing capabilities, boasting a crushing strength of 68 MPa (about 9,860 psi), a static bending strength of 105 MPa (about 15,230 psi), and a modulus of elasticity of 17,060 MPa (about 2,474,000 psi). For builders planning slab layouts, mature logs range from 50 to 80 cm in diameter, making them well-suited for medium-width river boards or split-slab table designs.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Clarisia racemosa | |
| Colour / texture / grain | Brown; texture medium; grain straight or interlocked; interlocked grain marked but not frequent | |
| Specific gravity (12% MC) | 0.69 | about 43.1 lb/ft³; a 2-inch-thick slab weighs about 7.2 lb per sq ft |
| Monnin hardness (12% MC) | 4.6 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 6.5 % | green to oven-dry |
| Total radial shrinkage | 3.1 % | green to oven-dry |
| Ratio St/Sr | 2.1 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.52 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 22 % | |
| Thermal conductivity | 0.23 W/(m·K) | |
| Crushing strength (12% MC) | 68 MPa | about 9,860 psi |
| Static bending strength (12% MC) | 105 MPa | about 15,230 psi |
| Modulus of elasticity (12% MC) | 17,060 MPa | about 2,474,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately 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 2 – inside or under cover (dampness possible) | |
| Drying | rate normal; distortion: slight risk; checking: slight risk; collapse: no known specific risk; casehardening: yes | |
| Suggested kiln program temperatures | 53–62 °C | about 127–144 °F |
| Machining | blunting high; saw teeth: stellite-tipped; cutting tools: tungsten carbide | |
| 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).
Frequently Asked Questions
How dimensionally stable is Guariuba next to an epoxy river?
Guariuba exhibits a total tangential shrinkage of 6.5 % and a total radial shrinkage of 3.1 %, yielding an St/Sr shrinkage ratio of 2.1. Its coefficient of volumetric shrinkage is 0.52 % per % moisture content, with a fiber saturation point of 22 %. Because tangential shrinkage is roughly double the radial movement, quartersawn boards offer the highest dimensional stability alongside cured resin. Slabs must be seasoned to target equilibrium moisture content prior to fabrication to prevent movement from stressing the wood-epoxy bondline. When sealing and pouring, follow the epoxy manufacturer’s technical instructions for edge preparation.
What drying risks should woodworkers anticipate with Guariuba?
CIRAD records Guariuba’s drying rate as normal, accompanied by a slight risk of distortion and a slight risk of checking, with no known risk of cellular collapse. However, casehardening is a confirmed risk during drying, and quartersawn material is prone to end checking during kiln operations. Standard industrial drying schedules run at temperatures between 53 °C and 62 °C (about 127 to 144 °F). Sealing board ends before drying and ensuring stress-relief conditioning helps produce flat, check-free blanks ready for resin casting.
How does Guariuba machine, and what tooling is recommended?
Guariuba causes a high blunting effect on standard cutting edges. The CIRAD data recommends using stellite-tipped teeth for saw blades and tungsten carbide tooling for planing and shaping. While straight-grained sections mill predictably, the interlocked grain can make it difficult to obtain a smooth surface. Taking light passes with freshly sharpened carbide cutters minimizes surface tearout along both the live edges and wide faces.
What is the durability and insect resistance of Guariuba?
The heartwood of Guariuba is rated durability class 3 (moderately durable) against wood-decay fungi. It is classified as Class D (durable) against both termites and xylophagous dry wood borers, with borer vulnerability limited to the demarcated sapwood. Heartwood treatability is class 3 (poorly permeable), and its natural durability corresponds to use class 2, covering indoor uses or sheltered locations where temporary dampness can occur. For indoor dining tables and desks, the heartwood offers long service life.
What are the primary joinery properties and documented end-uses?
Nailing and screwing performance is rated as good, ensuring reliable anchor points when securing tabletops to steel or wooden bases. Beyond river tables, CIRAD lists Guariuba for high-class cabinetwork, fine furniture, glued laminated timber, moulding, interior joinery, flooring, and indoor staircases. Thanks to its density and fine working qualities, the species is also recognized as an effective substitute for birch (Betula spp.), maple (Acer spp.), or boxwood (Buxus spp.).
Does Guariuba require CITES documentation?
No. Guariuba (Clarisia racemosa) is not listed in the CITES Appendices under the Washington Convention (2025). It can be legally acquired, transported, and utilized in custom furniture manufacturing without CITES-specific trade controls.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Guariuba has a documented thermal conductivity of 0.23 W/(m·K), which provides moderate thermal insulation typical of dense hardwoods and helps avoid localized thermal gradients between wood and epoxy sections in climate-controlled rooms. (Source: CIRAD Tropix 7 technical sheet: Guariuba.)