Grade 10 woodwork Materials – Adhesives Notes

1. (a) Identify and outline the sub-sub-strands:
   • Types of adhesives
   • Characteristics of adhesives
   • Application of adhesives in Woodwork
   • Importance of adhesives in Woodwork
2. (b) Identify types of adhesives used for bonding materials.
3. (c) Describe the characteristics of adhesives used in Woodwork.
4. (d) Use adhesives to bond materials in Woodwork (safe, correct technique).
5. (e) Appreciate the importance and correct use of wood adhesives.

1. Types of adhesives (common in Kenya)

• PVA (Polyvinyl Acetate) / White wood glue: water-based, easy to use, dries clear — best for indoor joints (e.g., frames, furniture). Often sold in hardware stores as "wood glue".
• Epoxy resin (two-part): strong, gap-filling, water-resistant — good for structural joints, repair of rotten sections, outdoor use when properly formulated.
• Polyurethane (PU) glue: moisture-curing, very strong bond (expands slightly) — useful for exterior furniture; needs clamping and careful dosing.
• Contact adhesive (solvent-based / neoprene): bonds laminates and veneers; both surfaces are coated and allowed to become tacky before pressing together.
• Cyanoacrylate (superglue): quick bond for small parts and repairs; brittle for large structural joints.
• Animal (hide) glue: traditional wood glue that can be reversed with heat and moisture — used in restoration and traditional joinery.

2. Important characteristics of adhesives

When choosing an adhesive, consider:

• Strength: tensile and shear strength — will the bond carry load?
• Open time / Working time: how long you can reposition parts before it sets.
• Setting/Cure time: how long until full strength is reached.
• Gap filling: ability to fill uneven surfaces or gaps.
• Water and weather resistance: important for outdoor pieces or wet environments.
• Viscosity: runny vs thick — affects how it spreads and soaks into wood.
• Sandability/paintability: can you sand or paint the glued surface afterward?
• Health & safety: fumes, flammability, and skin irritation — solvent-based adhesives need ventilation and PPE.

3. Applications in Woodwork

• Joinery (edge-to-edge, butt joints, scarf joints): PVA or hide glue is common for interior joinery.
• Assembly of furniture frames and chairs: PVA for indoor; PU or epoxy where moisture resistance is needed.
• Veneering and laminating: contact adhesive for pre-glued laminates; PVA for veneers with clamps and cauls.
• Repairs and structural bonding: epoxy for gap-filling and strengthening.
• Small fixes and quick repairs: cyanoacrylate for tiny breaks and dowel ends.

4. Why adhesives matter in Woodwork

• They create strong, often invisible joints that keep pieces together without metal fasteners.
• Allow joining of different materials (wood-to-wood, wood-to-metal, laminates).
• Improve durability and finish of furniture and decorative items.
• Reduce reliance on nails and screws, preserving wood strength and appearance.
• Some adhesives add water-resistance for outdoor use and extend life of products made from local timbers like pine, eucalyptus and cypress.

5. Practical: how to use adhesives safely and correctly

Materials & tools: chosen adhesive (PVA, epoxy, etc.), brushes or spreader, clamps, clean rags, sandpaper, gloves, safety goggles, mask (for solvents).

6. Safety and environment

• Always work in a ventilated area when using solvent-based adhesives (contact adhesives, PU, some epoxies).
• Wear gloves and eye protection. Avoid skin contact with glues like epoxy and cyanoacrylate.
• Do not inhale fumes — use a mask if recommended by the product label.
• Dispose of rags with solvent residues safely (risk of spontaneous combustion) and follow local waste rules.
• Store adhesives out of reach of children and in their original containers with labels intact.

7. Suggested learning experiences (classroom & practical)

1. Demonstration: Teacher shows correct gluing with PVA and clamping technique. Students observe cleaning squeeze-out and clamping pressure.
2. Hands-on group project: In groups of 3–4, make a small picture frame or spice rack using PVA glue and hand tools. Emphasise measuring, fitting and clamping.
3. Adhesive comparison experiment: Prepare three identical small wood lap joints. Glue one with PVA, one with epoxy, one with contact adhesive. After curing, test which carries more weight by adding known weights until failure. Record observations in a table.
4. Field visit / supplier talk: Visit a local hardware shop to identify adhesives, ask about uses and prices (learn to choose cost-effective materials available in Kenya).
5. Repair task: Individually repair a broken wooden item using an appropriate adhesive (teacher assesses technique and safety).
6. Reflection & appreciation: Students write short notes on why the chosen adhesive was suitable and what environmental/safety considerations they followed.

8. Assessment ideas

• Practical assessment: students glue and assemble a small project, judged on joint quality, correct adhesive choice, clamping, cleanup and safety.
• Short written test: identify types, list characteristics, and select correct adhesive for given scenarios (indoor shelf, outdoor bench, veneer).
• Record & report: submit experiment data comparing adhesives and explain results.

9. Quick reference (choose adhesive)

10. Tips for Kenyan students

• Buy small quantities of suitable adhesives from local hardware (read the label for indoor/outdoor use).
• Practice good surface preparation — clean and flat surfaces give the strongest bonds.
• When working outdoors or with damp timber (e.g., eucalyptus), choose moisture-resistant glue.
• Always follow manufacturer instructions for mixing ratios (especially epoxy) and cure times.