läten

Löten, also known as soldering, is a joining process in which two or more metal items are permanently connected by melting and flowing a filler metal into the joint. The filler metal, or solder, has a melting point below the base metals, so the original parts are not melted. When the solder cools, it forms a metallurgical bond that provides electrical continuity and mechanical strength.

Soft soldering is the common form used in electronics and plumbing. It employs low-melting filler alloys, typically around 180 to 250 Celsius. Tin–lead solders were historically standard, but lead-free alloys such as tin–copper or tin–silver–c copper are now common due to health and environmental concerns. Flux is essential to remove oxides and promote wetting of the metal surfaces. Hard soldering, or brazing, uses higher-melting-point fillers and stronger joints, often requiring more heat and stricter surface preparation.

The process relies on heat provided by a soldering iron, hot air, or a furnace, together with solder and flux. Surfaces to be joined should be clean and properly prepared, sometimes pre-tinned. Excess heat or moisture can damage components or boards, and desoldering tools or wick may be used to correct mistakes.

Applications range from electronics assembly and repair to plumbing, jewelry making, and metalwork. In electronics, precise temperature control and appropriate flux are important to avoid damage. Health and environmental considerations lead to the preference for lead-free solders and adequate ventilation and handling procedures.