What are two common post-braze cleaning methods?

• A. Abrasive blasting and painting.
• B. Hot water/alcohol wash and ultrasonic cleaning; mechanical cleaning as needed.
• C. Dipping in oil and filing.
• D. No cleaning is required.

Answer: (B)

Removing flux residues after brazing is essential because they can be corrosive and weaken the joint if left behind. The two common post-braze cleaning methods are a hot water wash with a solvent such as alcohol to dissolve and carry away residues, followed by drying; and ultrasonic cleaning, which uses high-frequency sound waves in a cleaning solution to create cavitation that loosens and lifts deposits from joints and hard-to-reach areas. When residues are stubborn, mechanical cleaning with brushes, picks, or scrapers is used as needed to physically remove what the other methods couldn’t. Abrasive blasting and painting aren’t typical for post-braze cleaning, as blasting can damage surfaces or spread debris and painting wouldn’t address residual flux. Dipping in oil or filing isn’t standard cleaning practice, and skipping cleaning would leave flux behind, risking corrosion and degraded joint performance.