How to assemble and startan oxy-acetylene torch?
How to assemble and startan oxy-acetylene torch?
The versatility and portability factors of an oxy acetylene torch have made it a popular choice for cutting and welding operations. While the torch can be operated on a variety of materials with varying sizes, it takes some practice and experience to do a good job. Below are some of the techniques to set up the torch and get you started in the right direction.
Before you begin using the oxy acetylene torch, check the steps listed below to ensure proper assembly of components, andappropriateand safe working conditions:
Inspect the cylinders and valves – As the name suggests, the oxy acetylene torch comprises of oxygen and acetylene stored in steel cylinders under high pressure. Make sure you test the cylinders for leaks prior to use. Even if you do not use the torch frequently, test the cylinders regularly and note the date tested to keep track of the usability of the cylinders and the safety of the operation.
One of the major safety hazards is poorly maintained cylinder valves. Grease and oil that come in contact with oxygen can cause it to catch fire and burst into flames. Even the oils from the palm of your hands can be hazardous. It is highly advisable to use gloves while handling the torch so as to prevent contaminating the valves. You should also check the valves for any residual pressure. It is also a good practice to store the cylinders in upright position when not in use.
Check the regulators – Regulators have measurement gauges to measure the pressure of the underlying gases. Ensure that the gauges are marked clearly and are easy to read. Always remember to use acetylene under 15 psig of pressure.
Similar to cylinder valves, regulators must also be maintained to keep them oil and grease free. Since the regulators play a key role in regulating the pressure of the gases, it is highly important to maintain the regulator under proper working conditions to ensure safety.
Examine the hoses – Hoses are a key delivery component as they connect the regulator to the torch. Hoses are generally color coded (acetylene is red and oxygen is green) and are available in various sizes depending upon the welding or cutting needs. Examine the hoses for wear and tear. Ensure that hoses are not twisted too tight while being stowed to avoid the development of cracks. Hoses should be securely fastened to the torch head using brass sockets. Poorly maintained hoses are the most common source of gas leak and pose a great risk to the welding operation.
Torches, welding/cutting tips and other attachments – Oxygen and acetylene are mixed in mixing chamber of torches and are ignited at the tip to generate the high temperatures required for cutting or welding. Torches and cutting tips need to be free from dirt and debris to ensure clean and optimal burning of the fuel (acetylene). You can use a fine, round metal file to clean the tips and torch head.
Follow key safety measures – Safety should be the number one priority. Always be aware of people around you. It is critical to equip yourself with proper safety gears including welding gloves to safeguard your hands and welding goggles to protect your eyes from flame and gases. In addition, there are components that can be attached to the torch itself as an extra layer of protection. Good practices include installing check valves to prevent backflow of oxygen and acetylene into the hoses and regulators that can cause explosion, and using a flashback arrestor as a backup to check valves.
Based on the actual needs of welding and cutting, there may be a few parameters that need to be adjusted:
- Fuel flow – The pressure at which the acetylene (fuel) comes in contact with oxygen is a key aspect in determining the optimal operation of the torch. Acetylene pressure should be around 5-8 psi and not greater than 8 psi under any circumstances.
- Oxygen flow – It is a common misinterpretation that fuel alone results in the high temperatures required for cutting or welding. In fact, it is oxygen that plays the crucial role in determining the heat gradient. Hence it is important to understand the oxygen flow best suited for the task at hand. For welding, it is recommended to set the oxygen at 5 to 7 psi. For cutting, it is recommended to set the oxygen at 15 to 25 psi.
- Welding/cutting tipsize- It is important to understand the type and thickness of the workpiece that needs welding or cutting. Selecting the size of welding/cutting tip accordingly is very critical to complete the job efficiently.
Actual operation of the torch
Only after the aforementioned prerequisites and parameters have been completed should you begin to operate the oxy acetylene torch.
- To start the operation, open the cylinder valves to allow the gases to flow into the torch via the hoses. While the oxygen valve can be opened completely, acetylene should be opened half way through only as acetylene tends to become unstable if opened too much.
- Once the gases are mixed in the mixing chamber of the torch, it is a good practice to vent out some mixture and blow-off any debris present at the tip. Then, it is time to light the torch. It is recommended to use a spark lighter as opposed to a butane lighter for safety reasons. Always tilt the torch away from you while lighting.
- Once the flame is obtained, turn the acetylene valve till you get a roaring flame and adjust both the gases to get the desired flame. Too much acetylene will result in a yellowish flame due to lack of oxygen. Too much oxygen cools the flame resulting in wastage of gases and can also oxidize the workpiece. One technique to obtain the optimal flame is to start with excess acetylene and a yellowish flame, then increase the oxygen levels to obtain a blue cone. Control the oxygen to obtain a distinct and small cone of flame with solid boundaries. This is the desired flame with the highest temperature.
- Moving the torch at the right speed and holding the tip at the correct angle is very critical.
- To shut down, first close the acetylene flow, followed by the oxygen flow.