What is the preferred solder for joining copper, iron, or steel?

When joining copper, iron, or steel, silver solder is preferred due to its excellent properties that enhance the strength and durability of the joint. Silver solder has a higher melting point compared to lead solder, which helps in producing a stronger bond that can withstand higher temperatures and stresses. The alloy typically consists of silver, copper, and sometimes zinc, which allows for strong adhesion to various metals while minimizing the risk of oxidation during the soldering process.

Moreover, silver solder provides good flow characteristics, ensuring that it can penetrate small gaps between the materials being joined. This is particularly important in situations where a strong, lasting connection is needed, such as in plumbing or metal fabrication applications.

Lead solder, while easier to manipulate, contains lead which presents health hazards and is not as strong as silver solder. Gold solder is primarily used for jewelry and is not commonly employed for mechanical or structural joints involving copper, iron, or steel. Copper solder does exist but is less optimal compared to silver solder in terms of strength and versatility across different metals.