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Design & Technology

Components, joints and adhesives

Joining metal

Metal joints can be made by brazing, soldering, welding or using rivets.


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 is a type of brazing which works at lower temperatures.

  • Soft soldering is used to make permanent joints between copper, brass, tin-plate or light steelwork, and is normally used to join components to electronic circuit boards.
  • Hard soldering is used for stronger joints.


A man uses a welding torch to join two sheets of metal.

In welding, two pieces of metal are melted along the joints - fusing together as they cool. No filler is used. A filler rod may be used for a really strong joint.

Machine screws

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


snap head, countersunk head, pan head, flat head, pop rivet

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

Pop rivets are used where there is only access to one side of the work. They are used to join thin sheets of material together.

Back to Resistant materials index

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