True or False: Flux should be applied with a brush to the ball tube and fittings.

Applying flux with a brush to the ball tube and fittings is a common practice in soldering and brazing. The purpose of flux is to prevent oxidation during the heating process, which can inhibit the proper bond between the metals being joined. When flux is applied with a brush, it allows for a controlled and even distribution of the material over the surfaces to be soldered or brazed. This ensures that the entire joint area is adequately protected and promotes better capillary action for the solder or filler material during the process.

Using a brush provides the flexibility to reach into tight spaces and ensures that all necessary areas receive the appropriate amount of flux. It also allows the user to apply more flux in areas that may require additional protection or where the surface may be more prone to oxidation. This is why brushing on flux is the recommended method, making the statement true.

In contrast, other application methods mentioned in the options, like using a syringe or spray, may not provide the same level of control and uniformity, which can affect the quality of the joint.