Soldering

Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a relatively low melting point. Soft soldering is characterized by the melting point of the filler metal, which is below 400 °C (752 °F).[1] The filler metal used in the process is called solder.

Soldering is distinguished from brazing by use of a lower melting-temperature filler metal. The filler metals are typically alloys that have liquidus temperatures below 350°C. It is distinguished from welding by the base metals not being melted during the joining process which may or may not include the addition of a filler metal.[2] In a soldering process, heat is applied to the parts to be joined, causing the solder to melt and be drawn into the joint by capillary action and to bond to the materials to be joined by wetting action. After the metal cools, the resulting joints are not as strong as the base metal, but have adequate strength, electrical conductivity, and water-tightness for many uses. There is evidence that it was employed up to 5000 years ago in Mesopotamia.[3]