Soldering and Brazing

Soldering and Brazing
Soldering is a process of joining two metals by using another low temperature metal alloy. The metal used for the joining purpose is called solder. Solders are of two types:
1. Hard solder (alloy of copper and zinc)
2. Soft solder (alloy of tin and lead)
Process
The surfaces to be joined are cleaned and are placed on each other. A flux is employed to prevent oxidation. Zinc chloride is commonly used for this purpose. The soldering iron is heated either electrically or by some external heat. Then the hot end is dipped into the flux and solder is pressed against the surfaces to be joined. A joint is formed by melting the solder.
Applications
Soldering is widely used for sheet metal work and in radio and television work for joining wires.
Advantages
1. Joining cost is low
2. Equipment is very simple and cheap
3. Good sealing in fabrication as compared to other processes like rivet, spot weld and bolts
4. It provides a positive electrical connection
5. Due to low operating temperature the properties of base metal are not affected
Disadvantage
1. Joints formed are weak