Characteristics of natural glues
Casein Type adhesives
Applications |
• tropical woods;
• structural lamination,
• panel and flush door covering;
• may produce glue lines with a thick appearance. |
Availability/ using |
• requires careful two-step mixing with water. |
Typical working time # |
15 to 45 minutes |
Clamp time # |
2 to 8 hours |
Cured working properties |
• cures hard, sands readily, but dulls cutting tools rapidly;
• permanently stains the surface of high-tannin woods such as oak and mahogany. |
Cured properties |
• excellent strength, rigidity and durability;
• highly creep resistant;
• some gap-filling ability. |
Long-term properties |
• high-grade formulas have good moisture and solvent resistance;
• low-grade formulas have lower moisture resistance;
• can be subject to bacterial and fungal attack unless preservative is added. |
# depending on glue formula, moisture content of workpieces, working temperature, atmospheric humidity etc
Fish Type adhesives
Applications |
• light-duty, wood-to-wood bonding;
• natural nonwood materials (such as cloth, metal and bone) to wood. |
Availability/ using |
• ready to use;
• can be coloured with dyes etc;
• refrigerate to extend shelf life. |
Typical working time # |
15 to 30 minutes |
Clamp time # |
2 to 4 hours |
Cured working properties |
• cures hard;
• machines and sands well;
• compatible with stains and finishes;
• reversible with water. |
Cured properties |
• good strength, rigidity and creep resistance;
• not as strong as hide glue. |
Long-term properties |
• Excellent heat and solvent resistance;
• poor water resistance;
• glue layers desiccate with time and becomes brittle. |
# depending on glue formula, moisture content of workpieces, working temperature, atmospheric humidity etc
Hide Type adhesives
Applications |
• good combination of versatility, compatibility and strength;
• edge- and face-gluing, assembling joints; veneering, repairing and bonding natural nonwood materials to wood.
• also used for sizing, a wood conditioner and a grain filler. |
Availability/ using |
• granules -mix with water and heat to 140°F before use;
• ready-to-use liquid hide glues also available;
• add water if glue thickens;
• add urea or salt to retard gel rate;
• can be coloured with dyes etc. |
Typical working time # |
1 to 10 minutes |
Clamp time # |
10 to 90 minutes |
Cured working properties |
• Cures very hard;
• machines and sands well. |
Cured properties |
• excellent strength, rigidity and creep resistance;
• thick glue layers can be brittle. |
Long-term properties |
• resistant to moderate heat and moisture levels, despite reversibility;
• good solvent resistance and shock resistance;
• glue layers desiccate with time and becomes brittle. |
# depending on glue formula, moisture content of workpieces, working temperature, atmospheric humidity etc
Rice & wheat paste adhesives
Applications |
• bonding porous, pliant materials (such as paper, cloth and leather) to wood;
• commercial formulas require no cooking and are easy to use. |
Availability/ using |
• mix with water and cook before use (if required);
• add preservative to prevent mould growth;
• can be coloured with dyes etc. |
Typical working time # |
15 to 20 minutes |
Clamp time # |
3 to 6 hours |
Cured working properties |
• Cures soft and flexible;
• Easily cut with hand tools;
• compatible with stains and finishes;
• reversible with water. |
Cured properties |
• not strong enough for most structural wood-to-wood bonding. |
Long-term properties |
• subject to bacterial and fungal attack unless preservative is added. |
# depending on glue formula, moisture content of workpieces, working temperature, atmospheric humidity etc