Excluding aluminum and magnesium alloys, what filler metal is commonly used for brazing most ferrous and non-ferrous metals?

• A. Bronze
• B. Silver (Ag)
• C. Tin
• D. Copper

Answer: (B)

A filler metal for brazing needs to wet surfaces well, flow into the joint by capillary action, and provide a strong, ductile bond across a wide range of metals without melting the base metals. Silver-based brazing alloys meet these conditions exceptionally well, giving reliable wetting on both ferrous and non-ferrous surfaces and forming strong, durable joints with good corrosion resistance. They offer a versatile melting range that lets you braze many different metals with a single family of fillers, which is why they’re commonly used for general brazing.

Bronze fillers can work but generally require higher temperatures and don’t flow as readily on diverse metals. Tin-based solders are often used for low-temperature or electronics applications and don’t provide the same strength and compatibility for many structural brazes. Copper fillers exist, but they can limit joint properties and may require more flux control and handling. Because of their balance of flow, strength, and compatibility, silver-based filler metals are the best general choice for brazing a broad set of ferrous and non-ferrous metals.