Courbaril (Jatoba) Slabs in Epoxy River Tables

Using Courbaril in Custom Epoxy River Tables

Courbaril (Hymenaea courbaril), frequently referred to in woodworking as Jatoba, is an exceptional tropical hardwood known for furniture, cabinetwork, and flooring. In custom epoxy river tables, Courbaril slabs offer rich color, distinctive grain patterns, and remarkable physical resilience. However, successfully pairing dense hardwood slabs with liquid casting resin requires a clear understanding of wood movement and dimensional stability.

Dimensional Shrinkage Properties of Courbaril

All natural timbers expand and contract as their moisture content fluctuates with environmental humidity. Understanding the baseline shrinkage values of Courbaril from green to ovendry conditions helps woodworkers anticipate how boards behave over time.

Tangential vs. Radial Movement and Grain Orientation

The relationship between tangential and radial shrinkage is a critical consideration when selecting live-edge slabs. In Courbaril, tangential shrinkage is 8.5%, which is roughly double the radial shrinkage rate of 4.5%. This proportional difference means that flatsawn faces experience substantially more dimensional change across their width than quartersawn faces.

When preparing slabs for an epoxy river pour, grain orientation directly dictates how the wood will interact with the cured resin:

• Flatsawn slabs will exhibit wider seasonal expansion and contraction along the tabletop surface, placing greater shear stress on the resin interface.
• Quartersawn boards show reduced surface movement because radial movement governs their width, offering greater dimensional stability.
• Volumetric shrinkage at 12.7% confirms that total volume loss from green to dry is notable, underscoring the absolute necessity of working exclusively with thoroughly seasoned timber.

Best Practices for Epoxy River Tables with Courbaril

Epoxy resin cures into a rigid plastic matrix that does not expand or contract in response to ambient relative humidity. Because Courbaril continues to respond to atmospheric moisture, builders must follow key practices to ensure a long-lasting bond:

• Dry to a Stable Moisture Content: Slabs must be dried thoroughly to an equilibrium moisture content matching the indoor environment before any resin work begins. Pouring over wood with residual moisture can cause adhesion failure, warping, or resin clouding.
• Apply a Meticulous Seal Coat: Applying a thin seal coat of epoxy to all exposed edges and live-edge faces prevents trapped air within the wood pores from escaping into deep-pour resin as bubbles. Sealing also establishes a solid mechanical foundation for the primary pour.
• Allow for Seasonal Movement in Table Base Mounting: Never secure a solid Courbaril tabletop to a rigid metal or wooden base with fixed, unslotted screws. Use slotted mounting brackets or expansion clips that allow the wood to expand and contract across its width without pulling apart the epoxy river seam.
• Surface Durability: In industrial applications, Courbaril is chosen for flooring, railroad crossties, and tool handles due to its shock resistance. In a dining or conference table, these properties mean the tabletop naturally resists dents and everyday impact wear.

Sources

Shrinkage and species data are sourced from the USDA Wood Handbook (FPL-GTR-282).

Published October 28, 2026. Sources are linked in the text.

Header image: original graphic by BigEpoxy.com.