What is the effect of poor fit-up on filler metal consumption?

• A. Has no effect on filler metal use.
• B. Decreases filler metal consumption.
• C. Increases filler metal requirement and can cause voids or incomplete bonding.
• D. Only affects cooling rate.

Answer: (C)

Poor fit-up creates larger or irregular gaps in the joint, which means more space must be filled by the filler metal. Since brazing and soldering rely on capillary action to draw filler metal into a clean, tight joint, a bigger gap not only requires more material but can also reduce how effectively the metal wicks into the joint. As a result, you end up needing more filler metal to fill the space, and if the gap isn’t properly bridged or aligned, voids or incomplete bonding can form, compromising the joint quality.