Shielding gas pressure regulator

The pressure regulator turns the high cylinder pressure into a constant, lower working pressure for the torch. Without it, the gas will blow your setting on the torch to pieces and you'll get a dirty weld with pores. Set the pressure so that the gas volume fits the welding – more is not better, it just causes turbulence and sucks in air. Check the gauge regularly to see if the pressure stays constant. If the weld suddenly becomes porous or the gas hisses, it's usually the regulator or the cylinder that's the problem.