Piquia in Custom Epoxy River Table Builds
Piquia (referring botanically to Caryocar nuciferum, Caryocar villosum, and other Caryocar species) is a dense hardwood harvested across Latin America, including Brazil, Costa Rica, Guyana, Peru, and Suriname. While commonly used in heavy construction and industrial applications, its warm coloration and substantial strength make it an intriguing candidate for furniture makers. Designing a wood and epoxy river table with Piquia requires an understanding of its physical properties, especially how its density and movement behave along a cured resin interface. According to technical data from the CIRAD Tropix research program, here is what woodworkers should know when working with Piquia slabs.
Appearance, Texture, and Surface Characteristics
Piquia heartwood ranges from yellowish white to pale beige, categorised overall as light brown. The sapwood is whitish to creamy white and is not clearly demarcated from the heartwood. The wood features a medium texture and slightly interlocked grain.
When milling slabs, CIRAD notes that Piquia can develop a woolly surface due to tension wood. Slabs may also release internal stresses during sawing, requiring woodworkers to take light passes and true their faces carefully before incorporating them into an epoxy pour.
Weight, Hardness, and Mechanical Strength
Piquia is a heavy wood, with a specific gravity of 0.81 at 12% moisture content. That places its dry weight at about 50.6 lb/ft³, which translates to roughly 8.4 lb per square foot for a 2-inch-thick tabletop slab. Tabletops made from Piquia will be quite heavy and require sturdy bases.
Its hardness is rated at 5.0 on the Monnin hardness scale. The Monnin scale is a French testing standard where higher values indicate harder material; it is not a Janka measurement. Mechanically, mature Piquia demonstrates high stiffness and strength, with a modulus of elasticity of 17,270 MPa (about 2,505,000 psi), a static bending strength (MOR) of 100 MPa (about 14,500 psi), and a crushing strength of 59 MPa (about 8,560 psi).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Caryocar nuciferum, Caryocar villosum, Caryocar p.p. | |
| Colour / texture / grain | Light brown; texture medium; grain interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.81 | about 50.6 lb/ft³; a 2-inch-thick slab weighs about 8.4 lb per sq ft |
| Monnin hardness (12% MC) | 5.0 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 8.2 % | green to oven-dry |
| Total radial shrinkage | 5.7 % | green to oven-dry |
| Ratio St/Sr | 1.4 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.45 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 29 % | |
| Thermal conductivity | 0.26 W/(m·K) | |
| Crushing strength (12% MC) | 59 MPa | about 8,560 psi |
| Static bending strength (12% MC) | 100 MPa | about 14,500 psi |
| Modulus of elasticity (12% MC) | 17,270 MPa | about 2,505,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class D – durable | |
| Dry-wood borer resistance | Class D – durable (heartw. durable but sapw. not | |
| Heartwood treatability | Class 3-4 – poorly or not permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate normal to slow; distortion: high risk; checking: high risk; collapse: no known specific risk; casehardening: yes | |
| Suggested kiln program temperatures | 53–65 °C | about 127–149 °F |
| Machining | blunting normal; 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).
Shrinkage, Stability, and the Epoxy Interface
When bonding wood directly to casting resin, dimensional stability determines whether the wood-to-epoxy bond will remain intact over time. Piquia has a fibre saturation point of 29%. Its total shrinkage from green to oven-dry is 8.2% in the tangential direction and 5.7% in the radial direction.
The ratio of tangential to radial shrinkage (St/Sr) is 1.4, which represents a balanced ratio that lowers the risk of severe cross-sectional cupping compared to woods with wider ratios. However, its coefficient of volumetric shrinkage is 0.45% per 1% change in moisture content. Because the wood moves appreciably with humidity shifts, slabs must be dried thoroughly to an interior equilibrium moisture content before casting. Any substantial dimensional shift after casting can place severe shear stress on the resin bondline.
Drying Risks and Fabrication Considerations
Drying Piquia requires patience. CIRAD reports a normal to slow drying rate with a high risk of checking and a high risk of distortion. Casehardening is also noted as an active risk, though there is no known specific risk of cell collapse. Recommended kiln schedules suggest temperatures between 53 °C and 65 °C (about 127 °F to 149 °F).
For tooling and joinery:
- Machining: Piquia exhibits normal blunting on tools. CIRAD recommends using stellite-tipped saw teeth and tungsten carbide cutting edges.
- Fasteners: Nailing and screwing hold well, but pre-boring is strictly necessary due to the density of the wood.
- Gluing: CIRAD explicitly notes that due to the wood’s high specific gravity, gluing must be performed strictly in compliance with established codes of practice to achieve reliable adhesion.
Natural Durability, End-Uses, and CITES Status
Piquia heartwood is classified as Durability Class 3 (moderately durable against xylophagous fungi) and Class D (durable) against dry-wood borers and termites. However, heartwood treatability is rated Class 3-4 (poorly or not permeable), meaning preservative treatments do not easily penetrate. Its natural durability places it in Use Class 2 (interior or under cover, where dampness is possible).
In international trade, Piquia is not listed in the CITES Appendices (Washington Convention 2025). CIRAD documents its common end-uses as current furniture or furniture components, interior joinery, exterior joinery, carpentry, heavy carpentry, industrial or heavy flooring, vehicle or container flooring, ship building, boxes, and wood frame housing.
Is It a Good Epoxy Table Wood?
Piquia can make a durable, attractive epoxy river table, but it requires careful preparation. Its high density (0.81 specific gravity) and high risk of distortion and checking during drying make moisture verification critical before casting. The slightly interlocked grain, potential for woolly surfaces from tension wood, and internal stress release during milling demand sharp carbide tooling. For builders who ensure their slabs are fully dried and properly surfaced, Piquia offers high rigidity, an even medium texture, and a clean light-brown aesthetic that pairs well with deep pour resins.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: CIRAD notes that while Piquia heartwood is durable against dry-wood borers, the sapwood (which is 2 to 5 cm thick) is not, and the sapwood is not clearly demarcated from the heartwood—inspect any live edge carefully for beetle activity before pouring epoxy. (Source: CIRAD Tropix 7 technical sheet: Piquia.)