Introduction to Yellowheart for Epoxy Tabletop Builds
Yellowheart (Euxylophora paraensis), also known by the trade name Pao amarello, is a distinctive Latin American hardwood harvested primarily in Brazil. Documented extensively by the CIRAD Tropix technical sheet, this species is renowned for its striking color. Freshly milled heartwood displays a bright yellow hue that gradually tones down to a warm yellowish light brown upon exposure to light and air. With its fine texture and visual warmth, Yellowheart offers a vibrant natural contrast when embedded beside tinted or deep-pour clear epoxy resin.
Beyond its looks, Yellowheart brings substantial density and structural strength to custom furniture, cabinetwork, and interior joinery. However, its high weight, specific drying behaviors, and dense grain structure require deliberate preparation before pouring an epoxy river.
Pros and Cons for River Tables
Pros:
- Balanced movement ratio: With a total tangential shrinkage of 6.5 % and radial shrinkage of 5.7 %, the tangential-to-radial shrinkage ratio is 1.1. A ratio this close to 1 indicates minimal internal distortion and a very low tendency to cup across slab faces.
- High natural durability: CIRAD rates the heartwood as Durability Class 1 (very durable against decay fungi) and Class D for resistance against dry-wood borers and termites, qualifying it for use class 4 applications.
- Standard tool friendliness: Despite high density, the blunting effect on tools is normal, allowing the use of ordinary cutting tools and ordinary or alloy steel saw teeth.
- Exceptional rigidity: With a modulus of elasticity of 19,460 MPa (about 2,822,000 psi) and crushing strength of 80 MPa (about 11,600 psi), tabletops exhibit extreme stiffness under heavy loads.
- Regulatory status: Yellowheart is not listed in the CITES Appendices (Washington Convention 2025).
Cons:
- High checking risk: The CIRAD data identifies a high risk of surface checking and end-checking during drying, along with a documented risk of casehardening.
- Significant slab weight: A specific gravity of 0.81 means a 2-inch-thick slab weighs approximately 8.4 lb per sq ft (about 50.6 lb/ft³), demanding robust table bases.
- Tearout risk during surfacing: While the grain can be straight, it is often slightly interlocked, requiring extra attention during planing and sanding.
- Impermeable heartwood: Heartwood treatability falls into Class 3-4 (poorly or not permeable), meaning deep resin penetration into raw pores requires meticulous surface prep.
- Unclear sapwood transition: Sapwood measures from 3 to 5 cm thick and is not clearly demarcated from heartwood, potentially yielding lower durability along slab edges if sapwood remains present.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Euxylophora paraensis | |
| Other trade names | Pao amarello | |
| Colour / texture / grain | Yellow; texture fine; grain straight or 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) | 5.5 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 6.5 % | green to oven-dry |
| Total radial shrinkage | 5.7 % | 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 | 21 % | |
| Thermal conductivity | 0.26 W/(m·K) | |
| Crushing strength (12% MC) | 80 MPa | about 11,600 psi |
| Static bending strength (12% MC) | 119 MPa | about 17,260 psi |
| Modulus of elasticity (12% MC) | 19,460 MPa | about 2,822,000 psi |
| Decay (fungi) resistance | Durability class 1 – very 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 4 – in ground or fresh water contact | |
| Drying | rate normal to slow; distortion: slight risk; checking: high risk; collapse: no known specific risk; casehardening: yes | |
| Suggested kiln program temperatures | 48–60 °C | about 118–140 °F |
| Machining | blunting normal; saw teeth: ordinary or alloy steel; cutting tools: ordinary | |
| 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).
Build Notes: Working with Yellowheart in the Shop
Slab Selection
Yellowheart logs typically span from 40 to 80 cm in diameter. When selecting slabs or dimensional boards for an epoxy build, closely examine the edges. Because sapwood runs from 3 to 5 cm thick and is not clearly demarcated from the heartwood, any live-edge features must be inspected for softness or bug entry, as sapwood does not share the same natural durability as mature heartwood. Account for the physical weight in your design: at 12% moisture content, wood density sits at about 50.6 lb/ft³, so large river dining tables will require heavy-duty legs and mechanical fasteners.
Drying and Stability Next to Epoxy
Epoxy does not shrink or expand with humidity changes, so surrounding timber must remain exceptionally stable. Yellowheart has a fibre saturation point of 21 % and a volumetric shrinkage coefficient of 0.61 % per % moisture content. Its overall tangential shrinkage (6.5 %) and radial shrinkage (5.7 %) produce a very favorable 1.1 ratio, which limits cupping. However, Yellowheart experiences a normal to slow drying rate and carries a high risk of checking and casehardening, especially in thicknesses greater than 41 mm. CIRAD drying schedules utilize kiln temperatures between 48 and 60 °C (about 118 and 140 °F). Verify that lumber has been thoroughly and uniformly dried to interior equilibrium moisture levels before locking it into an epoxy pour.
Machining
On the Monnin hardness scale—a French test where higher values reflect greater hardness—Yellowheart registers at 5.5 (note that this is not a Janka rating). Despite this firmness, the blunting effect on blades remains normal. Standard steel cutters and alloy steel blades handle the wood without excessive dulling. Because the species exhibits slight interlocked grain, take shallow passes during jointing, planing, and wide-belt sanding to prevent grain tearout along the bright yellow surfaces.
Sealing and Gluing Considerations
CIRAD notes that because of Yellowheart’s high specific gravity, gluing must be performed strictly in compliance with proper practice. The heartwood is poorly permeable (Class 3-4 treatability), meaning seal coats will sit close to the perimeter pores. Prior to pouring the main epoxy river, thoroughly clean all bonding edges and apply a dedicated epoxy seal coat per your resin manufacturer’s instructions. Sealing blocks trapped air from escaping out of end-grain pores into the liquid resin, preventing bubbles while establishing a dependable mechanical bond.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: For sourcing boards or lumber batches, CIRAD Tropix notes that Yellowheart appearance grading follows ATIBT rules, with available commercial grades including FAS (First And Second), n°1 Common and select, and n°2 Common. (Source: CIRAD Tropix 7 technical sheet: Yellowheart.)