Some metal objects can be made from one piece of metal. But others have to be made from a number of different pieces. Metal can be cut with an ‘oxyacetylene torch’. This torch uses the gases oxygen and acetylene which burn together at over 3,000° C. This is hot enough to cut through steel by melting it. Lasers are used to concentrate heat and cut through metal very quickly and accurately.
When a metal is heated it can melt. If two almost-melted edges are placed together and allowed to cool, they will form a strong joint called a weld. Riveting and soldering are other permanent ways to join metals.
A gas torch can be used to melt the edges of two pieces of metal. They then fuse together with some added molten metal. When the metals cool they form a strong joint.
The rivet is pushed through holes in overlapping plates so that the pointed end pokes through. This end is hammered flat to hold the pieces tightly together.
Soldering is used like glue to join delicate pieces of metal. Solder is an alloy of tin, lead and antimony. Molten solder is applied to the joint where it fuses the pieces together.
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