On oxyacetylene brazing kits, what ratio and pressures are typical?

• A. Pressure Regulators, 1:1 Ratio, 5 PSIG & 5 PSIG
• B. Regulators, 2:1 Ratio, 10 PSIG & 5 PSIG
• C. Regulators, 1:2 Ratio, 15 PSIG & 5 PSIG
• D. Regulators, 1:1 Ratio, 3 PSIG & 3 PSIG

Answer: (A)

A neutral flame is the target for brazing, which means balancing the gas streams so the flame isn’t extra oxidizing or fuel-rich. In practice, that balanced, neutral condition is achieved by setting both regulators to similar, modest working pressures. About 5 psi on the acetylene side and 5 psi on the oxygen side is a common, reliable setup. This equalizing of pressures helps maintain a stable, clean heat output that lets the filler metal flow properly and prevents overheating or contamination of the joint. Using higher acetylene pressure with the same oxygen (a fuel-rich mix) risks a carburizing effect and poor joint quality, while too-low pressures can fail to provide enough heat for brazing larger joints. So the typical configuration favors equal pressures around 5 psi for both gases to produce the appropriate neutral flame for brazing.