Like regulators for inert gas welding, oxy/gas regulators have two gauges: The high pressure gauge reads bottle pressure; the low pressure gauge reads gas pressure between the bottle and the torch. Adjust the acetylene and oxygen regulators to read about 3 to 4 psi. If you're using a cutting tip, you'll need more oxygen pressure-about 20 to 25 psi, but the acetylene remains the same. Also note that these pressures can vary depending on the size of the tip you're using and the thickness of the material you're welding. These numbers are good for most mild steel sheetmetal, though.