Even a beginner TIG welder wouldn’t argue the use of shielding gas, especially argon and the importance of the appropriate gas pressure during an active welding session. But one of the challenges that many welding pros, including the experienced ones have to face is to know how much pressure or flow of argon is required by a TIG welding project.
TIG welders in general focus more on the flow rate than the pressure because the flow rate is what results in the appropriate argon pressure, which is usually 15-25 PSI. Keep the flow rate between 15 and 25 CFH or 35 CFH depending on the build of the consumable and its parts.
Let’s expand the above thoughts a little bit and understand the various factors that help you determine the accurate argon pressure and flow rate.
What Does Gas Pressure Mean?
As you know argon is a shielding gas, the pressure argon should be at while TIG or any other type of welding is measured in PSI or pounds per square inch. It actually lets you know how much force the stream produces. So, you can take it as the indicator of the stream’s strength.
Are Flow Rate and Gas Pressure the Same Things?
While PSI gives you an estimate of the force created by the stream, flow rate gives you another reading which is the rate at which gas is being released. Welders use CFH or cubic feet per hour to understand this particular factor. Unlike PSI, CFH is mostly about consistency which, if not adjusted properly, leads to inconsistent stream, thereby causing poor weld flow.
I discovered some controversies about the significance of PSI and CFH concerning the efficiency of weld, but what I found is that PSI is more about efficiency than consistency. Neither PSI nor CFH should be left out of your considerations when it comes to an ideal TIG welding setup.
However, consistency is something that you cannot afford to lose, and it means you should emphasize more on the flow rate than the gas pressure. Welders in general know what happens when the gas flow rate isn’t set properly.
Most welders make a mistake by assuming that the higher flow rate or pressure of argon brings better protection. Again, some people think quite the opposite that only a moderate or low gas flow rate should be followed. The reason behind the thought of the second group is that TIG welding typically required a lower flow of gas than MIG welding.
Well, the truth is a little bit complicated. Excessive flow of gas causes turbulence and creates swirling currents. Unwanted contaminants existing in the air find their way into your work that can cause annoying arc wandering. Too low flow is likely to get disturbed. So, it doesn’t bring good results either.
So, you should err on the side of argon flow rates to make sure your weld receives proper argon coverage, and there is no turbulence. While using the shielding gas, you need to take breaks in order to allow the gas pressure to build back up.
For a better understanding of this pressure, welding professionals use another term called CFM or cubic feet per minute. You can take it as an alternative to CFH, but such usage is specifically meant for less gas flow.
What Pressure Should Argon Be For TIG Welding?
Since more welders keep asking questions about the flow rate, only a handful of them seem to be concerned about the gas pressure. All these make the understanding of PSI almost irrelevant to a welding job when compared to flow rate. At this point, I would like to provide an answer which might not be something very definitive or precise, but it’ll still help you form an opinion.
As some experienced welders suggest (I learned from their expert opinions, though), 15 PSI to 25 PSI should be enough for most TIG welding applications. In some cases, a higher pressure might be required, and that shouldn’t exceed 30 PSI.
When it comes to flow rate, I am glad to offer a more definitive idea because most professionals talk about it and provide very similar numbers.
How Do You Find Ideal Flow Rates?
If you are a MIG welding enthusiast and a regular user of argon, you probably know that the flow rate needs to be between 35 CFH and 40 CFH. In TIG welding, the rate needs to be lower, somewhere between 15 CFH and 25 CFH.
Whether the rate should be higher or lower depends on some other factors like consumables and cup sizes. Let me explain these variables. TIG welding projects require the use of several consumables. You need a nozzle as well as a collet which comes paired with a collet body or a gas lens. The desired quality of your finished weld is what tells you which one to choose.
If you’re working on a welding project where applications are critical but the weld quality must be high, a gas lens beats a collet body which is good for practice or non-critical applications. Gas lens reduces turbulence increasing argon coverage whereas, with a collet body, argon can spiral becoming more turbulent as it exits the nozzle.
You cannot disregard the shape, diameter, and length of the nozzle. In TIG welding, 1/16 of an inch is the typical measurement of a nozzle. It means that the diameter of the inside portion of a nozzle is 7/16 inch if it is a #7 nozzle.
Screwed securely onto the gas lens or collet body, the nozzle introduces argon to your weld, thereby being critical to the formation of different lengths of the laminar flow or shielding profile.
The term ‘Laminar flow’ means a type of flow specific to fluid or gas in which the flow is smooth and regular without turbulence.
Look at the table below to see how the flow rate needs to be changed in accordance with different nozzle sizes and components of the consumables, and metals being used.
| Electrode Diameter (Inch) | Cup Size(#) | Gas Lens (CFH or L/MN) | Collet Body (CFH & L/MN) |
| 0.020 | 3, 4, 5 | 5-8 or 3-4 | 5-8 or 3-4 |
| 0.040 | 4, 5 | 5-8 or 3-4 | 5-10 or 3-5 |
| 1/16 | 4, 5, 6 | 5-10 or 3-5 | 7-12 or 4-6 |
| 3/32 | 6, 7, 8 | 8-10 or 4-5 | 10-15 or 5-7 |
| 1/8 | 7, 8, 10 | 8-12 or 4-6 | 10-18 or 5-9 |
| 5/32 | 8, 10 | 10-15 or 5-7 | 15-25 or 7-12 |
| 3/16 | 8, 10 | 12-25 or 6-12 | 20-35 or 10-17 |
| 1/4 | 10 | 20-35 or 10-17 | 25-50 or 12-24 |
The numbers on the above chart are specific to a TIG welding project where you may weld non-ferrous metal using 100% argon as the shielding gas. However, you’ll need to make considerable changes if the project involves aluminum. Let’s look at another table.
| Electrode Diameter (Inch) | Cup Size(#) | Gas Lens (CFH or L/MN) | Collet Body (CFH & L/MN) |
| 0.020 | 3, 4, 5 | 5-8 or 3-4 | 5-8 or 3-4 |
| 0.040 | 4, 5 | 5-10 or 3-5 | 5-12 or 3-6 |
| 1/16 | 4, 5, 6 | 7-12 or 4-6 | 8-15 or 4-7 |
| 3/32 | 6, 7, 8 | 10-15 or 5-7 | 10-20 or 5-10 |
| 1/8 | 7, 8, 10 | 10-20 or 5-10 | 12-25 or 6-12 |
| 5/32 | 8, 10 | 12-25 or 6-12 | 15-30 or 7-14 |
| 3/16 | 8, 10 | 15-30 or 7-14 | 25-40 or 12-19 |
| 1/4 | 10 | 25-45 or 12-21 | 30-55 or 14-26 |
You might have noticed how the flow rate of argon or any other shielding gas changes with the different nozzle and cup sizes, and metals. So, you should consider adjusting the flow rate considering the components you’re using.
Final Thoughts
I would like you to note a few more things about argon pressure in TIG welding. The longer the column of the laminar flow, the better you’ll weld, given that all other factors are okay. For this particular condition to be met, you need a longer nozzle with a larger diameter.
A longer nozzle contributes to the better formation of the argon flow which gets more developed and stable before exiting the nozzle. A long nozzle reduces the shear found between argon and the atmosphere.
Again, larger cup sizes require higher flow rates. If you are new to TIG welding, I think you won’t be using a very large cup. In that case, the flow rate shouldn’t exceed 20 cubic feet per hour.
Got more questions about argon pressure? Feel free to write to me. I’ll try to provide a useful solution. Safe welding until then!
