Using an Oxy-Acetylene Cutting Torch: Setting Up, Lighting, Using, Shut Off

Does the thought of using an oxy-acetylene cutting torch intimidate you? We feel you. After all, dealing with two tanks at risk of catching fire as you work sounds risky. You would rather have all your body parts firmly attached as you work, right?

Don’t let this safety risk stop you from using a cutting torch. The worst-case scenario you are thinking of doesn’t happen that often. If you have the right settings for the entire system, you can safely use an oxy-acetylene torch for all your projects.

But, it doesn’t stop there. You also need to properly set it up before starting with this device, the same way you’d set up an engine-driven welder the right way.

Not only that, you must light it and shut it off correctly. Yes, there are proper ways to do all that.

Don’t worry because we will show you that all these are not as hard as you think. By the end of this article, you’ll know how to use an oxy-acetylene torch. You’ll even be able to light it the right way!.

Best Kits

If you’re getting started cutting metal, you must get the piece of equipment that will work for your needs. We carefully reviewed a bunch of products, and these are our recommendations.

Company
Best value
Forney
Best luxury option
YESWELDER
Best cheap option
YESWELDER
Best wire
YESWELDER
Photo
Forney Easy Weld 261, 140 FC-i Welder, 120V, Green
YESWELDER Digital MIG-205DS MIG Welder,200Amp 110/220V Dual Voltage, Gas Gasless MIG Welding Machine MIG/Lift TIG/ARC 3 in 1 Multiprocess Welder
YESWELDER Stick Welder,125Amp Hot Start ARC Welder,Digital Display IGBT Inverter MMA Welder,110/220V Dual Voltage Portable Welding Machine
YESWELDER Flux Core Mig Wire, Mild Steel E71TGS.030-Diameter, 10-Pound Spool
What we like
Great value, wire feed control & accessories included
Digital display, impressive quality & adjustability
Impressive, cheap machine
Great gasless MIG wire at an unbeatable price as well.
Our rating
5/5
5/5
4.5/5
5/5
Customer review
"Welding 1/2” to 3/16” was a breeze!!"
"Awesome welder for the money"
"Definitely worth what I paid"
"Very, Very Impressed"
Best value
Company
Forney
Photo
Forney Easy Weld 261, 140 FC-i Welder, 120V, Green
What we like
Great value, wire feed control & accessories included
Our rating
5/5
Customer review
"Welding 1/2” to 3/16” was a breeze!!"
Best luxury option
Company
YESWELDER
Photo
YESWELDER Digital MIG-205DS MIG Welder,200Amp 110/220V Dual Voltage, Gas Gasless MIG Welding Machine MIG/Lift TIG/ARC 3 in 1 Multiprocess Welder
What we like
Digital display, impressive quality & adjustability
Our rating
5/5
Customer review
"Awesome welder for the money"
Best cheap option
Company
YESWELDER
Photo
YESWELDER Stick Welder,125Amp Hot Start ARC Welder,Digital Display IGBT Inverter MMA Welder,110/220V Dual Voltage Portable Welding Machine
What we like
Impressive, cheap machine
Our rating
4.5/5
Customer review
"Definitely worth what I paid"
Best wire
Company
YESWELDER
Photo
YESWELDER Flux Core Mig Wire, Mild Steel E71TGS.030-Diameter, 10-Pound Spool
What we like
Great gasless MIG wire at an unbeatable price as well.
Our rating
5/5
Customer review
"Very, Very Impressed"

How Does The Tool Work?

Before setting it up, you must first understand how it works to handle it properly. Not only that, this will allow you to get a cut of good quality. It is only possible if done correctly. For more serious jobs, we recommend using a plasma cutter, though.

This device allows oxygen to mix with acetylene to combust and produce a flame with a temperature exceeding 3000 C. This kind of flame is the only one hot enough to cut through mild steel, specifically any steel that only has a maximum of 0.3% carbon.

Steel has an ignition temperature ranging from 700 to 900 ℃. It is enough to remove components that protect it against oxygen while keeping it in solid form. It pre-heats steel for it to reach that temperature; a cherry red color on the steel will signify that it has been adequately preheated.

When it reaches the unprotected steel, an exothermic reaction occurs that causes it to form oxidized liquid steel or slag. Because steel has a higher melting point, this formed slag can easily be blown away by oxygen. This then reveals the solid steel that has not been oxidized.

The exothermic reaction is continuous as long as the tool is lit up and the flame hits the steel. This constant reaction prevents a crust from forming on the steel. It immediately occurs if the protection against oxygen is still present. Because no crust forms, the oxygen can now penetrate the exposed solid steel and cut through it.

Due to the gas present, the flame produced is the highest among all oxyfuel cutting processes. This means you can work much faster and of better quality than the other methods.

How Do You Set Up and Use An Oxy Acetylene Cutting Torch?

Large cylinder gas tanks. Hoses. Regulators. Valves. Torch. Setting up an oxy-acetylene torch can be an overwhelming experience with all these components. While we admit that setting it up is not a straightforward affair, it is still possible for beginners to do.

Setting up such a system is pretty standard. Still, you must first check for any unique instructions the manufacturer may have. The manufacturer’s instructions will always take precedence over the following standard instructions:

  1. Secure the tanks to a sturdy post, wall, or the like in an upright position. It is better to use cylinder carts if available since they will do a better job of keeping them in place.
  2. Check and remove any protective coverings placed on the tanks. But if no covers were previously covering them, clean the tanks first to remove any debris or dust that settled. Make sure to check the valves. When cleaning the valves, stand away from the opening and quickly turn it on and off. This short burst is enough to blow off the dust present.
  3. Ensure that the regulators to be connected to the valves of the tanks have matching threads. If not, connect the regulator to an adaptor first. Connect the other end of the adaptor to the valve. Screw them in place by hand first, then finish tightening the connection using a wrench that has a fixed opening.
  4. Identify which hoses are for which of the gasses respectively. The hose for acetylene is typically red and green is for oxygen. Attach the right hoses to the regulators of the right tanks without contaminating it with any kind of lubricant.
  5. Once the hoses are firmly in place, connect the other ends of the hoses to the handle of your torch.
  6. Connect it to its handle and tighten the nut by hand. Ensure that the valves on both the torch and the handle are closed.

After setting up, you still need to do some checks before attempting to light it. Make sure that the regulators are facing away from you when you do the following:

How to use an oxy-acetylene cutting torch

  1. Open the valves of both tanks, but do it slowly and only one at a time.

  2. Adjust the screws of the regulators so that the gauge will reflect a psi between 40 to 60 for the oxygen tank and 10 psi for the other tank.

  3. Slightly open the valves for both on the cutting torch.

    Ensure that the acetylene valve is not open by more than 1/8 of a turn or exceeding 45 degrees.

  4. Do a leak test on all the connected parts using a solution specifically for leak testing or a paste made using dissolved Ivory soap.

    Use it to coat the valves, hoses, and regulators and watch out for any bubbles that form after a few minutes. If present, it means a leak is present, and you need to adjust or tighten the connections.

  5. Repeat the leak test until no bubbles appear.

  6. After successfully doing a leak test, you can now light it up following the manufacturer’s instructions.

How to Light It to Get Start

Because of the gases involved, lighting up a cutting torch is done differently. Unlike other devices, it will not produce a flame with just a button push.

Most of the kits are lit up using this method:

  1. Slightly open the valve for the acetylene. Make sure that it does not exceed a half-turn.
  2. Use a flint striker or spark lighter to ignite the gas flowing out of the nozzle. Soot or black smoke may come out once it is lit up, which is considered normal. You can wait it out or adjust the valve to make the smoke disappear.
  3. Once the smoke is gone, slowly open the oxygen valve to remove all the yellow spots of the flame. Adjust to get a neutral flame needed for cutting. This neutral flame consists of a white, cone-shaped tip near the nozzle and a bigger blue core.

You should only use a flint striker to light it because using smaller lighting devices are too small. They will put you at risk of burning your hands as you light it up. Specifically, avoid matches and normal lighters. You must make sure that the tip is facing away from you. Watch out for other people and flammable objects.

But if it has its ignition device, skip the above steps and follow the instructions given.

How to Shut It Down When You Are Done

Because there is also no knob or button present to stop the flame, you must manually shut it down. Do it by cutting off the gas being supplied. There is a seemingly never-ending debate about which gas supply to switch off first. Is it oxygen followed by acetylene or acetylene, then oxygen?

While both methods are correct, manufacturers generally advocate shutting off the oxygen valve first before acetylene. This method allows the acetylene still flowing to blow off the soot that settles in the crevices of your torch. Any soot present can affect the seal of the gas valves and cause a leak.

Not only that, but this order also allows you to conduct a leak test before turning off the gas supply. Once the oxygen supply is off, then turn off the other. The presence of a small flame will indicate a leak if no gas is flowing. Early leak detection helps prevent an explosion.

Another advantage of cutting off the oxygen supply first is that mini flashbacks are less likely to occur. Despite most having protective features against it, flashbacks can still happen. Mini flashbacks occur in the form of a loud pop or bang. While generally considered harmless, mini flashbacks can still cause accidents.

If you are done with your work and need to return your equipment to its storage, you must follow the following steps:

  1. Turn off the gasses supplies by switching off the valves at their respective tanks.
  2. Purge the gas that remains in both hoses or gas lines by reopening the oxygen valve on the torch. It means the remaining gas in the hose will flow out. Close the valve once no more gas is flowing out.
  3. Repeat the purging with the other gas line. Make sure to purge both hoses separately.
  4. Once you finish purging, disconnect all components and store them properly.

When storing the tanks, make sure to keep them in a dry and airy location far away from any flammable objects. Always keep them in a vertical position.

Can You Cut Cast Iron With a Torch?

Have you ever attempted to cut cast iron using an ordinary blowtorch? If so, you may have realized that it is a futile effort. But if you are using a cutting torch to do so, the result will be different.

Because an oxy-acetylene torch has the highest flame temperature present. It can easily cut through even steel at least 200 mm thick. But when it comes to cast iron, it is also possible. It will not give you a clean result and is a bit harder to do.

Preheating the cast iron is crucial before you get started. This is done by setting the torch to produce a carburizing flame instead of a neutral flame with the highest possible temperature. This type of flame offers better preheating to the cast iron and stops oxides from rapidly forming. Preheating should be done from top to bottom and with more acetylene so that the heat will deeply penetrate the cast iron.

Once it is sufficiently preheated, make small semicircles around the preheated line to melt the iron. Finally, use the oxygen jet to blow off the molten iron and cut through it. You may need flux to help you get the work done.

Because of the complicated process, using this specific device to cut its way through cast iron is not the most common method. There are other methods specially developed for this purpose.

Can I Weld With It?

Are you wondering if you need to buy separate welding equipment if you already have a torch and need to do some welding? If so, we have good news. You can also use it for your welding needs. This process is known as oxy acetylene welding.

The metals are placed side by side, with a small gap between them. They are melted together by the flame created by the gases. The melted sections are already bonded to form a weld seam when they cool down. This type of welding can be considered if joining metals fast is your only concern. The welding joint formed is not as neat as the ones created by other welding methods.

A neutral flame is also used for welding, but you need to move your torch circularly. That way, the metals will melt and pool towards the small gap present between them. While the weld seam formed using this method is strong enough, you can also add filler material using a rod to increase its strength.

Contrary to its name, a cutting torch is not only used for cutting. You can also use it in different ways, making it a versatile tool that you must have in your workshop.

Do you turn on the oxygen or acetylene first on an oxy-acetylene cutting torch?

Once you’ve done all the regular safety checks, starting up the oxy torch is easy. You’ll have to set up torch. You will have to purge both valves separately, and you can start by turning on the fuel gas valve by 1/2 turn first. Ignite the flame and adjust it till it becomes normal. Once this is done, turn up the oxygen valve and bring it to a neutral flame.

How do you set the flame on a cutting torch?

You can start by turning on the acetylene valve by 1/8th of a turn and igniting the flame.

Now slow down the flame until the smoke is reduced to a minimum. You see the flame turning into a feather-like shape towards the end. Now turn on the oxygen valve slowly and watch the preheat flames appear. Adjust this until the neutral flame appears.

The neutral flame will be conical and sharp unless there is a low oxygen level. Both oxygen and acetylene need to be at adequate levels. Otherwise, the progress of the cut will be hampered.

What pressure should oxygen and acetylene be set at?

It’s safe to assume that an oxygen pressure of 40psi and acetylene pressure of 10psi is good to go. However, always check the machine’s manual. Adjust the flame until you see the neutral flame appear for a safe bet, and you’re all set to start.

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