Gluing Exotic Woods for Epoxy: CIRAD Bonding Notes Guide

CIRAD Bonding Notes and Wood Working Challenges

When selecting timber for solid wood panels or epoxy resin river tables, bonding performance dictates long-term stability. The CIRAD Tropix technical sheets provide specific gluing observations across dozens of tropical and temperate timbers. These notes alert builders to distinct chemical and physical hurdles, ranging from extreme density to resin exudation and wood acidity. Understanding these characteristics ensures that edge-to-edge glue joints hold and epoxy pours adhere cleanly without unexpected peeling or discoloration.

Wood	CIRAD note on gluing
Afzelia	Tends to split when nailing. Gluing may be difficult due wood extractives. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Agba	Wood fairly acid: risks of stain when gluing.
Alan / Alan-Batu	Risk of splitting when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Alep	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Amesclào	Tends to split when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Ananta	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Andok	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Angelim pedra	Tends to end checks when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Angelim vermelho	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Angelin	Tends to split when nailing. Gluing must be done with care (dry wood and smooth surfaces).
Angueuk	Tends to split when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Batibatra	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Bilinga / Opepe	Wood presents slight tendency to split when nailing. Wood is acidic: to be taken into account when gluing.
Billian	High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Bitis	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Bodioa	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Brown sterculia	Tends to split when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Cabreuva	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Ceylon Satinwood	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Chengal	High specific gravity and resin exudations: gluing must be especially performed in compliance with the code of practice.
Coconut wood	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Congotali	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Coula	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Cryptomeria	Tests performed on Cryptomeria from Réunion show that this species has good bonding ability and allows the manufacture of glued products meeting the regulatory requirements of the carpentry and construction markets. The reliability, visual rendering (removal of defects) and dimensional stability of these products will be better than those of solid wood, while improving material yields (recovery of small pieces of wood). The advantages of this species when using this assembly technique are its ease of machining, the absence of extractables rising after machining, its good wettability, its low density, and its good dimensional stability during installation.
Cumaru / Tonka	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Cupiuba	Pre-boring recommended to avoid splits. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Danta	Pre-boring is sometimes necessary. Tends to stain when gluing.
Difou	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Dina	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Ekki	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Essia	Risks of splits with thin dimensions. High specific gravity: gluing must be especially performed in compliance with the code of practice.
European Ash	Very porous and slightly acid: to be taken into account when gluing.
European Beech	Very absorbent: to be taken into account when gluing.
European Cherry	Acid glues may stain the wood on a long-term basis.
European Larch	Difficult gluing due to resin. Drying over 70°C practically eliminates this problem.
European Oak	Gluing must be done with care: wood is dense, slightly acid, rich in tanins, and prone to stain. Nail or screw corrosion if in contact with humidity.
European Poplar	Low tendancy to split when nailing. Very absorbing when gluing.
Eveuss	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Eyoum	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Giam	High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Goiabao	Risks of splits when nailing or screwing. Pre-boring recommended. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Gombé rouge	Keep sharp cutters in order to obtain a good finish in case of interlocked grain. Le bois du Gombé rouge se colle sans difficulté (carrelets 3-plis). Gombé towé wood is easy to glue (3-plies laminated scantlings).
Gombé towé	Gombé towé wood is easy to glue (3-plies laminated scantlings).
Grenadillo / Grenadille d’Afrique	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Idigbo	Wood fairly acid: to be taken into account when gluing (tend to stain).
Idéwa	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Itauba	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Kelat	Tends to split with nailing. High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Keledang	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Keranji	Very high specific gravity and extractive content: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Keruing	Resin exudations: to be taken into account when gluing.
Lati	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Limbali	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Macassar Ebony (Ebène Veinée d’Asie)	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Macucu de paca	Pre-boring necessary in presence of highly interlocked grain. Risks of end checks. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Mambode	Resin exudations: to be taken into account when gluing.
Manchiche	Easy to glue, but only for indoor use.
Manilkara	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Manniballi	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Maritime Pine	Difficult gluing for woods with a high percentage of resin. Drying over 70°C is recommended.
Massaranduba	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Mecrussé	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Merbau	Tends to split with nailing. High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Moabi	Tends to split when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Mora	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Moral	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Mountain Pine (Hooked Pine)	Even if the wood of Hooked Pine is less resinous than that of Scots Pine, it is necessary to take account of the presence of resin when gluing.
Mubala	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Muhuhu	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Muirapiranga / Bloodwood	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Mukulungu	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Niove	Tends to split when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Ogea	Surface often fuzzy. Assembling and gluing sometimes difficult due to warping of dried veneers.
Okan	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Olène	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Osanga	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Ovangkol	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Ozouga	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Pakuri	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Pau marfim	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Pau mulato	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Piquia	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Piquiarana	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Preciosa	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Pyinkado	High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Radiata Pine (European Plantation)	Wood glues easily with all types of adhesive. Due to the high permeability of wood, adhesives must have a high dry extract content. .
Red balau	Tends to split with nailing. High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Resak	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Rosewood Para	Very high specific gravity and high extracts content: gluing must be especially performed in compliance with the code of practice.
Sapucaia	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Scented Guarea (Bossé Clair)	Gluing Guarea cedrata may be difficult due to resin exudations.
Scots Pine	Sometimes resin exudations: to be taken into account when gluing.
Snakewood	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Sonokeling Rosewood	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Sougué	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Tamalan Rosewood	Very high specific gravity and high extracts content: gluing must be especially performed in compliance with the code of practice.
Tanimbuca	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Tasmanian oak	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Tatajuba	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Tchitola	Resin exudations: to be taken into account when gluing.
Timborana	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Uchy	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Utile	Wood fairly acid: risks of stain when gluing.
Vésámbata	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Vêne	High specific gravity and extracts: gluing must be especially performed in compliance with the code of practice.
Wacapou	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Wallaba	Tends to split when nailing. High specific gravity: gluing must be especially performed in compliance with the code of practice.
Wamara	Very high specific gravity: gluing must be especially performed in compliance with the code of practice.
Wamba	High specific gravity: gluing must be especially performed in compliance with the code of practice.
Wenge	Risks of splits when nailing. High specific gravity and wood tends to stain: gluing must be especially performed in compliance with the code of practice.
Yellow balau	Tends to split with nailing. High specific gravity: important that gluing be performed in compliance with the code of practice and instructions for the glue used.
Yellowheart	High specific gravity: gluing must be especially performed in compliance with the code of practice.

Data compiled by BigEpoxy from individual CIRAD Tropix 7 technical sheets (average values for mature wood).

Grouped Explainer: Understanding the CIRAD Bonding Notes

Dense and Heavy Woods: High and Very High Specific Gravity

The vast majority of exotic woods cataloged with gluing warnings share one major physical trait: elevated density. Species such as Ekki, Cumaru, Massaranduba, Snakewood, Angelim vermelho, and Ebène veinée d’asie are listed with very high specific gravity, while woods like Afzelia, Merbau, Okan, and Chengal feature high specific gravity. For these species, CIRAD consistently notes that gluing must be performed in strict compliance with the code of practice and the adhesive manufacturer’s instructions. Dense wood fibers yield smaller cell cavities, reducing the mechanical interlocking that standard adhesives rely upon. Achieving a sound bond on dense surfaces requires freshly planed or sanded faces, accurate joint mating, and carefully observed clamping pressure.

Resinous Woods and Natural Extractives

Natural chemical compounds can severely interfere with adhesive bonding and resin curing. CIRAD flags several species where resin or extractives pose direct challenges:

• Resin exudations: Species like Keruing, Mambode, Chengal, Scots Pine, and Scented Guarea (Bossé Clair) can bleed resin to the surface, creating a barrier that disrupts adhesion. For European Larch, drying over 70°C practically eliminates resin issues, and drying over 70°C is likewise recommended for resinous Maritime Pine.
• Interfering extractives: Afzelia, Keranji, and Rosewood Para contain high levels of extractives that can hinder glue penetration and chemical bonding.

Wood Acidity and Staining Reactions

Chemical reactions between wood extractives and adhesive formulations can cause bonding failures or dark discoloration. CIRAD highlights wood acidity in timbers such as Agba, Bilinga (Opepe), European Ash, and Idigbo, noting that staining risks must be taken into account when gluing. Similarly, Danta tends to stain during assembly, European Cherry may stain permanently when paired with acid glues, and European Oak is dense, slightly acidic, rich in tannins, and prone to staining under glue contact.

Porous, Absorbent, and Well-Behaved Species

At the opposite end of the spectrum, certain woods present bonding challenges due to extreme porosity. European Beech and European Poplar are noted as very absorbent or very porous, which can starve a glue joint if the adhesive sinks too rapidly into the end grain or face pores. Conversely, CIRAD highlights species that bond exceptionally well under proper conditions. Cryptomeria features good wettability, low density, and an absence of extractables rising after machining, while Gombé rouge and Gombé towé glue without difficulty, successfully used for 3-plies laminated scantlings.

What This Means for Slab Gluing and Epoxy Adhesion

Whether assembling an edge-glued panel or casting epoxy against a live-edge slab, these CIRAD notes guide your shop workflow:

• Fresh Mechanical Preparation: Because dense timbers close their grain quickly and oily woods push extractives back to the surface over time, all mating surfaces should be prepared immediately prior to bonding. A freshly abraded surface exposes sound wood fibers and promotes mechanical grip.
• Degreasing Resinous Timber: For species with resin exudations or oily extractives, wiping the joint face with a solvent before applying resin or adhesive removes localized surface oils that could inhibit wetting.
• Adhesive and Resin Compliance: Woodworkers must follow the resin maker’s technical data sheet for open time, working temperature, and application methods. For acidic or tannin-rich timbers, testing compatibility prevents unsightly chemical ring stains along the resin margin.

Pre-Glue and Pre-Pour Shop Checklist

1. Confirm Moisture and Drying History: Verify that timber has been properly dried. Resinous pines and larches benefit from the elevated drying temperatures noted in CIRAD sheets to set wood pitch.
2. Inspect Joint Tolerance: Joint edges must fit seamlessly with uniform contact, avoiding excessive pressure that could starve joints in dense hardwoods.
3. Execute Fresh Surface Prep: Sand or dress surfaces shortly before gluing or casting to eliminate oxidized layers and surfaced oils.
4. Wipe Down Resinous Edges: Use an appropriate solvent wipe on species prone to exudations to leave a clean, oil-free surface for resin attachment.
5. Review Data Sheets: Follow the adhesive and epoxy manufacturer’s data sheets for correct mixing ratios, spread rates, clamping guidelines, and cure conditions.

Sources

• CIRAD Tropix 7 technical sheets (index)

Published October 31, 2026. Sources are linked in the text.

Header image: original graphic by BigEpoxy.com.