Components

Components are often the used to join materials together. They are the smaller parts that make up a product. Different components are used to join plastics, wood and metals together. Adhesives are used to glue materials together.

Components made from resistant materials and are typically bought ready-made. The most common used in Design and Technology are nails, screws, hinges and catches.

Joints

Most products are made from multiple materials. Joints are therefore needed to join the pieces together when the product is fabricated or assembled.

Permanent and temporary joints

Permanent joints are intended to stay put throughout the product’s lifecycle. They may be assembled using adhesives, nails, rivets, or one of the heat processes of brazing, soldering or welding. Assembly jigs are often used to hold components in place while they are being joined. For example, the parts of a steel roof frame can be put into the jig and then welded together.

Temporary fixings usually involve components: such as screws, nuts and bolts, or one of the many knock-down (KD) fixings.

Joining plastics

Plastic products are often moulded to snap together during the assembly process. Permanent joints are created using adhesive, machine screws, rivets or bolts.

Joining wood

The method used for joining wood will depend on the product and its usage. Wood joints can be made with screws, nails and glues, or with frame joints, such as butt joints, halving joints, mortice-and-tenon, dovetail and box joints.

Screws

To insert screws two sizes of hole are needed. The main hole must be very slightly bigger than the shank of the screw so that the shank can move freely in the clearance hole. The first hole must be smaller than the core of the screw so that the core fits tightly into it.

Nails

Nails are cheaper and easier to use than screws and come in many shapes and sizes. To fix nails holes need to be drilled to prevent the wood from splitting, or when using hard woods.

Joining Metal

Metals joints are made by brazing, soldering, welding or rivets.

Brazing

Brazing is a way of bonding materials by melting a filler metal or alloy between the components. The filler metals used in brazing must have a lower melting point than that of the material being joined. Brazing forms very strong, permanent joints.

Soldering

Soldering is a type of brazing which works at lower temperatures.

Welding

Welding works when two pieces of metal are melted along the joints, the metals fuse together as they cool.

Machine Screws

Machine screws are screws used for joining metal components. Holes have to be pre-drilled into the component. They must have the correct internal thread.

Rivets

Rivets can be used to join metals, plastics and plywood. The rivet is placed in a hole drilled through both pieces of material. The end of the rivet is then beaten into a dome.  A tool called rivet set is then used to finish off the joint. Some rivets are countersunk.

Adhesives

Adhesives glue materials together. Different adhesives need to be used for different materials and product uses.

Adhesive types

The main types of adhesive are PVA (polyvinyl acetate), synthetic resin, epoxy resin, contact adhesive and acrylic cement.