Soldering and brazing are metal joining processes based on a lower melting point metal or alloy wetting the surface of a higher melting point metal. Solder is usually a lower temperature process based on lead and/or tin alloys, but may contain other metals for enhancement of various properties. Soft solder usually refers to use of lead-tin alloys and hard solder usually refers to some silver content in the alloy. Brazing usually is based on copper or silver alloys and uses higher temperatures. Directionally, the lower the temperature, the less chance of warping the steel, but the lower the strength of the joint.
Properly tinned and soldered barrels are sufficiently durable for most shotgun applications. They are, however, succeptible to damage from hot salt blueing. They are easier to repair than are damaged brazed barrels.
