Soldering irons are tools commonly used in the electrical and electronics industry. They are designed to heat, melt and join two metal parts together with a solder joint, a process called soldering. Soldering irons come in a range of sizes and shapes, and the size and shape depend on the job for which it is used. Most common soldering irons are either electric or gas powered, and both use some form of heat source to heat the tip. The tip is the part that gets heated up and the solder is placed on and melted. When the soldering iron is used correctly, the solder joint should be strong and reliable.