Hard- Surfacing, Building Fusion Welding Carbon Welding Non-Ferrous Metals Heating & Heat Treating Braze Welding Welding Cast Iron Welding Ferrous Metals Brazing & Soldering Equipment Set-Up Operation Equipment For OXY-Acet Structure of Steel Mechanical Properties of Metals Oxygen & Acetylene OXY-Acet Flame Physical Properties of Metals How Steels Are Classified Expansion & Contraction Prep For Welding OXY-Acet Welding & Cutting Safety Practices Manual Cutting Oxygen Cutting By Machine Appendices Testing & Inspecting
4 Continued on next page... Always leave the wrench in place on the acetylene cylinder valve while the valve is open. However, when two or more cylinders have been manifolded together, it is sufficient to leave a wrench on one of the cylinders. The point is this: you should not be forced to waste time looking around for a suitable wrench should an emergency make it necessary to close the cylinder valve or valves without delay. Note: The cylinder-pressure gauge on each regulator shows you the pressure in each cylinder. In the case of both oxygen and acetylene, pressure is a rough measure of contents. If you are using a large cylinder of oxygen which when full contained 244 cf at 2200 psi and 700F (6.5 m3 at 15200 kPa and 200C), the cylinder is half-full when the cylinder-pressure gauge reads 1100 psi (517 kPa), so that you have 122 cf (3.2 m3) available. When the pressure in an acetylene cylinder is approximately 125 psi at 700F (862 kPa at 200 C) it is also true that the cylinder is about one-half full. However, if you are using a liquefied fuel gas, such as propane, cylinder pressure remains constant until virtually all the liquid has been vaporized. For that reason, regulators designed for propane service are seldom supplied with cylinder- pressure gauges. Liquid oxygen cylinders are equipped with liquid-level gauges which will indicate the amount of liquid oxygen remaining in the cylinder. Connecting Gas Supplies to the Torch Always use hose and hose connections made specifically for gas welding and cutting purposes. Oxygen hose has a green cover; acetylene hose has a red cover. Never interchange oxygen and acetylene hose. Do not use acetylene hose with propane unless you know that is acceptable for use with propane. (Hose with natural rubber liner is satisfactory for acetylene service, but not for propane service.) Make up all connections dry; do not use pipe-fitting compounds, thread lubricants, oil, or grease. All connections are designed with metal-to-metal seals. They do not require lubricants or sealants. However, they must always be made up wrench-tight, not merely hand-tight. Never force connections which do not fit. If you cannot run the threads together by hand with ease, either the threads are damaged, or you are trying to put together parts that were not made to go together. If the hose does not have connections on both ends, put these on next. Connection nuts for oxygen hose have right-hand threads, connection nuts for acetylene have left-hand threads. Instructions for installing hose connections are given in the Appendix