Fasteners, Adhesives, and Joinery
Fasteners, Adhesives, and Joinery
This domain tests selection and installation: nails, screws, bolts, connectors, glue, and joints. You need to match the fastener to load direction, material, and exposure.
Core rules
- Nails perform well in shear but withdraw easily; screws resist withdrawal better and are removable; bolts and connectors carry heavy structural loads.
- Use corrosion-resistant fasteners for treated wood and exterior work; check connector manufacturer approvals.
- Pre-drill near ends and for hardwoods to reduce splitting; keep fasteners away from edges according to code or manufacturer instructions.
- PVA glue needs clean, close-fitting joints and clamping pressure; polyurethane and epoxy tolerate more gap and moisture.
- Joint choice follows load: mortise-and-tenon and dovetail resist racking; dado and rabbet add shelf and cabinet strength; biscuits and dowels align but do not replace structural connections.
Worked example
A cabinet face-frame butt joint is glued and clamped with PVA. If the joint is starved because the clamps are too loose, the glue line is weak even though the adhesive is suitable. The fix is to flatten the joint, apply a thin even film, and clamp until cured. A gap-filling adhesive may be needed only where the joint cannot be made tight.
Traps
Using drywall screws for structural framing, nails where withdrawal matters, or exterior connectors without approved fasteners are common errors. Do not assume more glue means a stronger joint; excessive glue can prevent close contact.