Pehmeäjuotos

Pehmeäjuotos is the Finnish term for soft soldering. It is a soldering process used to join metals, typically at relatively low temperatures. Unlike brazing or welding, which involve much higher temperatures and melting of the base metals, soft soldering uses a filler metal with a melting point below 450 degrees Celsius (842 degrees Fahrenheit). This filler metal, known as solder, creates a metallurgical bond between the two workpieces.

The most common solders are alloys of tin and lead, although lead-free alternatives are increasingly used due to environmental and health concerns. Other elements like silver, copper, and bismuth are often added to modify the properties of the solder, such as its melting point, strength, and flow characteristics. Flux is an essential component in the soft soldering process. It is applied to the surfaces to be joined to remove any oxides or contaminants that would prevent the solder from wetting and bonding properly. The flux also prevents re-oxidation during heating.

The heating for soft soldering is typically done using a soldering iron, but other methods like torches or hot air guns can also be employed. The soldering iron transfers heat to the base metals, which then melt the solder. The molten solder flows into the gap between the parts by capillary action and solidifies upon cooling, forming a strong electrical and mechanical connection. Soft soldering is widely used in electronics for connecting components to printed circuit boards, in plumbing for joining pipes, and in various repair and assembly tasks where high temperatures are undesirable.