Abstract: Welding apparatus which includes a fuel container for liquefied gas, an oxygen generator, a burner nozzle, and a flow control system for conveying a controlled amount of gas and oxygen from the fuel container and oxygen generator to the burner nozzle for combustion. The oxygen generator includes a reactor which contains a catalyst for decomposing the oxygen generating compound to produce oxygen and water and accompanying heat. Heated oxygen and water from the reaction are carried to a collection chamber by a condenser system which condenses substantially all of the water. An evaporator system carries oxygen from the collection chamber to the flow control system. In one embodiment it is arranged in thermal association with the reactor so that the heat of the reaction is utilized to vaporize any water entrained in the oxygen coming from the collection chamber, thereby promoting proper combustion of the oxygen and fuel at the burner nozzle.