Working with Olon in Wood and Epoxy Tabletops
Olon (Fagara heitzii) is a Central and West African hardwood sourced from countries such as Cameroon, Gabon, Equatorial Guinea, the Republic of the Congo, and the Democratic Republic of the Congo. Documented thoroughly by the timber researchers at CIRAD Tropix, Olon features a distinctive heartwood ranging from light yellow to greenish yellow, often displaying a lustrous surface and a subtle ribbon-like figure on quartersawn sections. For builders crafting custom epoxy river tables, Olon provides an intriguing, bright aesthetic paired with predictable, moderate mechanical behavior.
Pros and Cons of Olon for Epoxy Builds
Before selecting Olon for an epoxy tabletop or live-edge river build, evaluate its working characteristics against shop requirements:
- Favorable shrinkage ratio: With a tangential-to-radial shrinkage ratio of 1.5, Olon exhibits a relatively low tendency toward cupping or warping.
- Moderate tabletop weight: At 12% moisture content, Olon has a specific gravity of 0.52 (about 32.5 lb/ft³), yielding a 2-inch-thick slab that weighs roughly 5.4 lb per square foot.
- Standard tool compatibility: Tool blunting is normal, and ordinary or alloy steel tooling easily handles the lumber.
- Low seasoning distortion: CIRAD Tropix rates the risk of distortion and checking during drying as slight, with no known specific risk of casehardening or cellular collapse.
- Trade status: The species is not restricted under CITES Appendices (Washington Convention 2025).
- Susceptible to wood-boring insects: Olon heartwood is rated Class S (susceptible) to dry-wood borers across all the wood, demanding prompt inspection and protective treatment.
- Prone to blue stain: The lumber discolors easily if exposed to damp or improper post-harvest conditions.
- Planing tearout: Slight interlocked grain can cause difficulties during surface planing.
- Silica and dust hazards: Silica content may be quite high, and the sawdust is sometimes an irritant in the workshop.
- Indoor use restriction: Natural durability places it in Use Class 2 (interior or under cover where dampness is possible); it is not recommended for exterior or permanently wet installations.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Fagara heitzii | |
| Colour / texture / grain | Light yellow; texture medium; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.52 | about 32.5 lb/ft³; a 2-inch-thick slab weighs about 5.4 lb per sq ft |
| Monnin hardness (12% MC) | 2.0 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 5.7 % | green to oven-dry |
| Total radial shrinkage | 3.8 % | green to oven-dry |
| Ratio St/Sr | 1.5 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.40 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 30 % | |
| Thermal conductivity | 0.18 W/(m·K) | |
| Crushing strength (12% MC) | 44 MPa | about 6,380 psi |
| Static bending strength (12% MC) | 72 MPa | about 10,440 psi |
| Modulus of elasticity (12% MC) | 12,410 MPa | about 1,800,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class M – moderately durable | |
| Dry-wood borer resistance | Class S – susceptible (risk in all the wood) | |
| Heartwood treatability | Class 2-3 – poorly to moderately 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: no known specific risk | |
| Suggested kiln program temperatures | 55–65 °C | about 131–149 °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). Notes. OLON is often confused with OLONVOGO (F. macrophylla, F. tessmannii), which is heavier and harder. |
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).
Hardness, Density, and River Table Stability
Olon has a Monnin hardness value of 2.0. The Monnin scale is a standard French hardness test where higher numbers reflect harder timber; it is not comparable to the Janka scale. A rating of 2.0 characterizes Olon as a moderately soft to medium hardwood, making it easy to cut, shape, and join, though it will benefit from careful support in heavy-wear dining table environments.
In river table construction, dimensional stability at the wood-resin interface is essential. Rigid cured epoxy cannot expand or contract with ambient moisture shifts. When wood expands or shrinks excessively, immense shear stress develops along the joint line. Olon has a total tangential shrinkage of 5.7% and a total radial shrinkage of 3.8% from green to oven-dry, alongside a fibre saturation point of 30% and a coefficient of volumetric shrinkage of 0.40% per % change in moisture content. Combined with its low St/Sr ratio of 1.5, Olon minimizes differential stress along the cast resin channel compared to high-movement hardwoods.
Build Notes: Slab Selection, Machining, and Finishing
Slab Selection: Commercial Olon logs generally span 55 to 80 cm in diameter, producing medium-width slabs suitable for bookmatched river table tops. The sapwood is relatively narrow at 1 to 2 cm thick and is not clearly demarcated from the heartwood. Because Olon is prone to blue stain fungi, inspect live edges and light-toned sapwood zones for gray or bluish streaks before designing clear-cast layouts.
Drying: CIRAD Tropix records a normal drying rate. Kiln drying programs typically run at temperatures between 55 °C and 65 °C (about 131 °F to 149 °F). Ensure the timber reaches equilibrium with your shop and intended indoor environment before casting resin, as proper moisture stabilization prevents bond separation.
Machining: While cutting edges made of ordinary steel or alloy steel remain sharp through normal blunting, planing requires light passes and sharp cutterheads to prevent tearout along areas of slight interlocked grain. Because silica content may be elevated and the fine sawdust can irritate skin and respiratory tracts, use active dust extraction and personal protective gear when sanding or routing molds. Olon holds fasteners securely, earning a good rating for screwing and nailing.
Sealing and Finishing: Olon features a medium texture. Prior to deep river casting, brush an epoxy seal coat along the live edges to seal open vessels and lock out air pockets that cause bubbles in the cured resin, following the resin manufacturer’s technical data sheet. When topcoating, film-forming or penetrating finishes applied evenly over both the wood and resin surfaces will protect against moisture cycling while highlighting the wood’s natural yellow luster.
Sources
Published October 30, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: Olon is frequently confused with Olonvogo (Fagara macrophylla, Fagara tessmannii), but Olonvogo is distinctly heavier and harder, so builders should verify log tags or measure board weight if a slab feels unusually dense. (Source: CIRAD Tropix 7 technical sheet: Olon.)