One of the most widely used cutting tools is the oxy-fuel or oxy-acetylene cutting torch, commonly referred to as the blow torch. Using a cutting torch is easy in theory. Many people find it difficult to use, let alone make a good cut.
It’s the reason it’s so crucial to have the right settings. Most of them have no idea about the proper settings, particularly the working pressure. That is why the work they make is of poor quality.
Summary
The best pressure settings depend on the thickness of the metal that you’re working with. For example, for a metal that has a thickness of 0.125 inches, the pressure will be 20/25 oxygen (PSIG) and 35 Acetylene (PSIG). The description outlines some general recommendations not meant to replace the manufacturer’s recommendations.
Best Set
Looking to upgrade your oxy-acetylene torch kit set? The table below includes our recommendations of kits when it comes to the best value option and the best high-end option. Make sure you can work safely and effectively!
Table could not be displayed.Oxy-Acetylene Cutting Torch Pressure Settings & Chart
Take a look at the oxy-acetylene pressure settings chart to understand what your torch should at for the most optimal results.
The thickness of metal in inches | Tip size | Pre-heat oxygen (PSIG) | Pre-heat oxygen (SCFH) | Cutting oxygen (PSIG) | Cutting Oxygen (SCFH) | Speed (IPM) | Acetylene (PSIG) | Acetylene (SCFH) | Kerf Width (inches) |
0.125 | 000 | 3/5 | 3/5 | 20/25 | 20/25 | 28/32 | 3/5 | 3/5 | 0.04 |
0.25 | 00 | 3/5 | 4/8 | 20/25 | 30/35 | 27/30 | 3/5 | 4/6 | 0.05 |
0.375 | 0 | 3/5 | 5/9 | 25/30 | 55/60 | 24/28 | 3/5 | 5/8 | 0.06 |
0.5 | 0 | 3/6 | 7/11 | 30/35 | 60/65 | 20/24 | 3/5 | 6/10 | 0.06 |
0.75 | 1 | 4/7 | 9/14 | 30/35 | 80/85 | 17/21 | 3/5 | 8/13 | 0.07 |
1 | 2 | 4/9 | 11/18 | 35/40 | 140/150 | 15/19 | 3/6 | 10/16 | 0.09 |
1.5 | 2 | 4/12 | 13/20 | 40/45 | 150/160 | 13/17 | 3/7 | 12/18 | 0.09 |
2 | 3 | 5/14 | 15/24 | 40/45 | 210/225 | 12/15 | 4/9 | 14/22 | 0.11 |
2.5 | 3 | 5/16 | 18/29 | 45/50 | 225/240 | 10/13 | 4/10 | 16/26 | 0.11 |
3 | 4 | 6/17 | 20/33 | 40/50 | 270/320 | 9/12 | 5/10 | 18/30 | 0.12 |
4 | 5 | 7/18 | 24/37 | 45/55 | 390/425 | 8/11 | 5/12 | 22/34 | 0.15 |
5 | 5 | 7/20 | 29/41 | 50/55 | 425/450 | 7/9 | 5/13 | 26/38 | 0.15 |
6 | 6 | 10/22 | 33/48 | 45/55 | 500/600 | 6/8 | 7/13 | 30/44 | 0.18 |
8 | 6 | 10/25 | 37/55 | 45/55 | 500/600 | 5/6 | 7/14 | 34/50 | 0.19 |
10 | 7 | 15/30 | 44/62 | 45/55 | 700/850 | 4/5 | 10/15 | 40/56 | 0.34 |
12 | 8 | 20/35 | 53/68 | 45/55 | 900/1000 | 3/5 | 10/15 | 48/62 | 0.41 |
Multi-hole cutting
Fuel gas
The recommended setting is for the fuel gas regulator to be set at 10 PSIG and the oxygen regulator at 45 PSIG. This recommendation applies when cutting less than 1.5-inch steel using propane, propylene, or natural gas.
Oxy-Acetylene
The recommended setting for multi-hole cutting is the oxygen regulator at 40 PSIG, with the acetylene regulator setting at 10 PSIG. As with the previous recommendation, this applies to cutting less than 1.5 inches thick steel. The cutting tip oxy acetylene pressure will depend on the size. The manufacturer’s recommendations should always be followed.
Single-hole welding and brazing
Start looking for the stamped single-hole tip to see what number it has. Both the fuel-gas regulator and the oxygen regulator should have the indicated setting. This recommendation is not the case for injector-style options.
If you see that the tip has the number “5” on it, that is the number at which both the oxygen and fuel gas pressure should be set.
Unlike the portable blow torch, these different components must be correctly set up. Doing so ensures a proper operation that can result in quality work. It also minimizes the risks of accidents, especially flashbacks and explosions.
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Here are the important steps to follow when setting up an oxy-acetylene torch:
How To Set Up An Oxy Acetylene Cutting Torch Pressure
- Ensure that the cylinders or tanks containing the two gases are properly secured and in an upright position.
Use a cylinder cart if available. Ensure that they are properly fastened or chained to a sturdy place like a beam or wall. They should never be knocked down during operation or when not in use. - Remove any coverings placed on the valve of the cylinder or tank.
But if protective covers were not used, remove any dust or debris that has settled inside the valves. It can cause the torch to malfunction. To do so, stand away from the valve’s opening or outlet (preferably on its opposite side). Turn the valve quickly about a quarter of the way and immediately close it. This quick release of gas will immediately blow away the dust or debris. - Connect the regulators to the valves but confirm that they have the same threads.
If not, use an adaptor to connect them. They must have a completely tight and secure fit for safety and proper monitoring of the pressure settings. Manually screw them by hand as tight as possible, and use a wrench with a fixed opening to finish tightening them. - Attach the proper hoses if they are not connected to the respective regulators.If you have already used them before, connect them to the same tanks as before. The standard practice is to use green hoses for oxygen and red hoses for acetylene. Never apply any oil, grease, or any form of lubricant to the hoses. Especially make sure not to apply it on its ends.
- Connect the torch handle to both of the hoses.Once securely attached, install the torch to the handle and manually tighten the nut. Check the valves on both the torch and its handle, as they must be closed before opening the valves of both cylinders.
- Turn the valve of the oxygen tank or cylinder until it is fully open.Locate the regulator’s adjusting screw and turn it clockwise until the gauge shows that the pressure being released is between 40 to 60 psi.
- For the acetylene cylinder, do a counterclockwise turn for the valve. Turn it only a quarter of the way.Turn the adjusting screw on the regulator until it releases gas, and the gauge shows 10 psi.
- Find the oxygen valve and open it slightly to allow it to start flowing.Do the same for the acetylene valve but do not open it by more than 45 degrees or a 1/8 turn.
- Do a leak test.Coat the valves and connections between the cylinder, hose, and regulators with a leak-test solution or a thin paste. It can be made by dissolving Ivory soap and using a clean brush for its application. A leak is present if you see any small bubbles on the coated surfaces after letting the solution sit for a few minutes.
- If leaks are present, you must retighten or reattach connections first and do another leak test before lighting the torch.
- Once no more leaks are present, follow the manufacturer’s instructions to light it up.
Remember to watch the flame as you use it. If it goes out as you’re working, stop and simply relight it. This occurrence is known as a backfire, and it happens when the torch itself and the metal being cut get into direct contact.
How to Light It
Lighting an acetylene torch is fairly easy, but you must follow the correct steps to do so. This mainly involves tinkering with the two valves of the cutting torch to get the right kind of flame. Also, make sure that both regulators show the right amounts of psi before lighting.
The following steps are the standard procedures but always check with the manufacturer for specific instructions:
- Open the acetylene valve with a half-turn first before using friction or spark lighter to create a flame coming from the torch. Never use a match. There should be a one-inch gap between the tip of the torch and the flame coming out of the lighter.
Using a match to light is risky. You may accidentally burn yourself once the flame comes out. Some also come with ignition devices, so manually lighting them up with a lighter is unnecessary.
- Black smoke or soot may come out together with the flame. Wait until it disappears before slowly opening the oxygen valve. It being released will remove any yellow sections on the flame, which is essential for a neutral flame.
- Adjust both valves to achieve a neutral flame. It must have a small, whitish or bright blue center and is clearly shaped like a cone.
When lighting it, make sure that the tip faces away from people or any flammable object to avoid any accident.

What should it be set at?
If you’re multi-hole cutting, you need the oxygen set at 40psi and the fuel at 10psi. Always check your equipment manual before you set your torch. Acetylene pressure must not exceed 9psi unless the tool is designed for it. It’s also dangerous to use acetylene above 15 psi as it becomes spontaneous and highly combustible in this setting.
Here’s a crucial question, especially when you’re just getting started with your blow torch. You will need expert guidance and safety procedures to handle the torch correctly. Here’s the full procedure below.
