1. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Unit 23 Using Gas Welding Equipment

2. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Gas Welding The burning qualities of a gas are used to heat, cut, and weld metals Compressed gases can be very dangerous The most popular fuel gases for welding are propane and acetylene Fuel gases must be mixed with oxygen before they will burn

3. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Safety Precautions Wear safety goggles and face shield at all times Obtain instructor’s permission before using any gas Store fuel gas cylinders and oxygen cylinders separately Keep cylinders upright and chained at all times Store cylinders in well-ventilated areas Do not put pressure on the hoses or equipment connected to cylinders Always check for leaks before using Never use equipment exposed to grease or oil Follow specific on/off procedures

4. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Safety Precautions (continued) Work only in areas free of flammable materials Always have fire extinguishers nearby Wear leather gloves and apron Always screw on caps when cylinder is not in use Always point equipment away from people and clothing Never leave clothing where it can be saturated by fuel gases or oxygen Learn to recognize combustible fuel odors Protect gas cylinder storage areas with locked fences or concrete enclosures

5. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Oxyacetylene Equipment Cart Cylinders Valves Regulators Gauges Hoses Torch assemblies

6. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Set Up Cylinder design features –Acetylene cylinder valve protected by a high collar –Acetylene valve turned on or off with a handle –Acetylene equipment color-coded red –Acetylene couplings have left-hand threads and notched fittings –Oxygen cylinder valve protected by a heavy cap –Oxygen color-coded green –Oxygen couplings have right-hand threads

7. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Leak Tests Leak tests should be performed when –equipment is first set up –cylinders are changed –odor of acetylene is present To test –Put a small amount of water in a jar or can –Add a drop or two of non-detergent hand soap –Use a 1'' paintbrush to get a soapy lather and apply gently around each fitting or any connection where gas can escape –Bubbles will form if there is a leak

8. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Torches Two types –welding –cutting Both types include a body/handle with hose connections and valves Tips are screwed onto the body Tips are available in different sizes A cutting assembly can also be attached to the handle

9. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Important Terms Weld: to join by fusion Fusion: to melt together Gas: any fluid substance that expands without limit Compress: to reduce in volume by applying pressure Flammable: burns easily Apparatus: objects necessary to carry out a function

10. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Important Terms (continued) Manifold: a pipe with two or more outlets Rig: a self-contained piece of apparatus assembled to conduct a specific operation Oxyacetylene: oxygen and acetylene Torch: assembly that mixes gases and discharges them to support a controllable flame Cylinder: long, round tank with extremely thick walls built to contain gases under great pressure

11. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Important Terms (continued) Valves and regulators: devices that control or regulate the flow of a gas Gauge: measures the gas pressure in a hose, tank, or manifold Hoses: flexible lines that carry gases Crack the cylinder: turning the gas on and off quickly to blow away any dust from the opening Purge the lines: remove undesirable/leftover gases in the welding hoses

12. Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED. Important Terms (continued) Carbonizing flame: excess acetylene present in the flame Neutral flame: correct balance of acetylene and oxygen in the flame Oxidizing flame: excess oxygen in the flame Tip cleaners: rods with rough edges designed to clean the hole in the welding tip Bleeding the lines: removing gases from all lines and equipment