In silver brazing, which type of flame is used to heat the base metals?

In silver brazing, the type of flame used to heat the base metals is the neutral flame. This type of flame provides a balanced mixture of oxygen and acetylene, ensuring that neither element excessively oxidizes nor carburizes the metal being brazed. The neutral flame is ideal for brazing because it produces a high-temperature flame that evenly heats the joint area without introducing impurities.

Using a carburizing or oxidizing flame can negatively affect the brazing process. A carburizing flame adds carbon to the metal, which can lead to unwanted chemical reactions and affect the bond quality. An oxidizing flame, on the other hand, can cause oxidation of the base metals, leading to poor adhesion of the filler material. Therefore, a neutral flame is preferred, as it maintains the integrity of the metals and promotes a strong, clean joint in silver brazing.