What is solder?

Solder is a type of fusible metal alloy particularly designed to join two metals together permanently. The solder wire typically has a lower melting point than the two metals, so when the heat is applied the solder melts first and binds together the metals before the metals melt. 

The process that uses solder is called soldering, which is a popular process in the electronics industry to solder PCBs and other electronic components, as well as in the jewellery and plumbing industries.

Types of solder

Different types of solder are used to suit specific types of applications. For example:

• Solder wires: These are the most commonly used type of solder, and are available in a range of wire diameters.
• Solder granules: Another widely used type of solder, they appear as small pellets and are most commonly used in jewellery making. Solder granules are also used for soldering tinning crucibles. 
• Paste solder: This is a type of sticky solder paste. It is popularly used for soldering in Printed Circuit Boards or PCBs.

Apart from these, solders can also be categorised based on the alloys used and their operating properties. These include:

• Soft solder: Composed of varying concentrations of tin, this type of solder is commercially available. The higher the percentage of tin, the greater the tensile strength the soft solder provides.
• Lead-free solder: As the name suggests, lead-free solder is devoid of any lead and hence has a lower melting point. The most common alloys used in lead-free solder may include tin, silver, copper, bismuth, or antimony, among other materials. This type of solder is particularly useful for eliminating hazardous materials and is popularly used in consumer electronics.

Applications

The chief applications of a solder can be found in:

• Pipework in plumbing
• Automobile radiator cores
• Electronics and electrical industry 
• Metalwork industry 
• Jewellery making industry 
• Glass work