Oxy-Acetylene Welding uses oxygen and acetylene gases to provide a superheated flame, 3600 K (3300 °C, 6000 °F), that melts metal, causing two pieces of similar metal to actually fuse into one piece. A third element, in the form of a welding rod (stick) is often used to strengthen the resultant weld by filling minute cracks caused by contraction during cooling and to act as a metallic "glue" in any areas that were not completely melted and joined during the weld.
Oxy-acetylene is the oldest type of welding. It is relatively slow, and requires a high skill level. Resultant weld seams tend to be rough, discolored, and somewhat brittle. Beginners are usually able to cut metal using an oxy-acetylene torch but cannot expect to make acceptable welds (joins) without considerable experience and practice.
Basic oxy-acetylene welding and cutting equipment consists of two pressurized tanks, one each of oxygen and acetylene, a pair of joined hoses that lead the welding torch that the welder holds in one hand while performing the operation. The tanks have regulating gauges that show pressure in pounds-per-square-inch. The size and shape of the welding/cutting flame is regulated by valves on the torch handle and accessory tips that can be added to the torch.
Oxy-acetylene usage is dangerous beyond the simple possibility of fire. Powerful explosions can occur if the two tanks of compressed gases are mishandled. Tanks should always be securely strapped into appropriate racks or carts to prevent tipping and damage.
Newer types of welding have all but eliminated oxy-acetylene welding, which is now used primarily for heavy-duty applications where appearance is not a prime concern. Electric welders of various types are easier to use, less dangerous, and produce better looking, and sometimes stronger, welds. Oxy-acetylene is still commonly used for cutting steel and can be used to cut thicknesses exceeding eight inches in one pass Oxy-acetylene cutting produces waste in the form of slag that runs as a liquid away from the cutting surface.
Safety concerns with Oxy-Acetylene welding:
- Use Acetylene gas at a pressure of 15 psi or less
- Use only undamaged equipment
- Be sure your working area is free of grease and oil
- Do not use Oxygen or fuel gas to blow dirt or dust off clothing or equipment
- Do not light a torch with matches or a lighter - use a striker
- Always make sure regulators have their adjusting screws released by turning them counter clockwise till free before opening cylinder valves
- Stand to the side of a regulator, not in front of it when opening cylinder valves
- Wear proper welding goggles, gloves, and clothing when operating Oxy-Acetylene equipment
- Pants worn while welding should not have cuffs
- Have a fire extinguisher handy when operating
- Always replace cylinder caps when finished using cylinders
- Do not rely on the color of the cylinder to identify its contents – read labels
- Use the correct regulator for the gas in the cylinder
- Use cylinders in an upright position only.
- Do not expose cylinders to ambient temperatures exceeding 130deg. F
- Do not carry lighters, matches, or other flammable objects when welding or cutting
- Be aware of your surroundings at all times
- Do not operate where others may interfere with you or your equipment
- Do not to let the welding flame or sparks hoses come in contact with hoses