MIG (metal inert gas) welding is a popular type of gas metal arc welding, and one of the most important parts about this type of welding is the gas pressure. It is crucial that you have the right amount of gas flowing for the material and environment you are working in.
To adjust the gas pressure on a MIG welder:
- Open the valve on the tank to clear debris
- Insert the gas regulator
- Adjust the knob of your gas regulator to around 30 cubic foot hours
- Turn on the welder and activate the gas valve
- Adjust the gas flow to 20 cubic foot hours for continuous flow
Now that you know the basic steps to adjusting the gas pressure on a MIG welder, we can go into more detail, so you have a better understanding of the process. While it might seem like an easy step to just skip over, it is really important that you set the shielding gas to the right level.
How Can I Adjust the Gas Pressure on a MIG Welder?
The first thing that you must understand about adjusting the gas pressure on a MIG welder is the purpose of the shielding gas. This important concept can have major impacts on the quality of your welding—for better or for worse.
Regulating the pressure of your shielding gas for MIG welding is important because:
- Too little gas flowing can result in possible contamination and excessive spattering.
- Too much gas flowing wastes gas.
- Gas pressure that is too high creates turbulence near the weld puddle that can compromise the strength of your weld.
What is even more important to understand is that you will likely have to adjust the pressure of the shielding gas for MIG welding whenever the conditions around the welding area change. A slight breeze often requires an adjustment for the gas pressure, but different materials also require different gas pressures.
Important Note: Be sure that you have the proper equipment and protective gear before you engage in any sort of MIG welding. Suggested gear includes heavy duty leather gloves, a leather jacket, sturdy boots, and a welding helmet. You should also keep the area clear of flammable items.
Secure the shielding gas tank to the MIG welder.
Your first step in adjusting the gas pressure on a MIG welder is to make sure that the bottle of shielding gas is securely attached to the MIG welder. There is typically a holder that the tank or bottle sits in.
Most MIG welders also have a chain that hooks around the tank of shielding gas to hold it in place. The exact configuration will vary from welder to welder. Some MIG welders also have designs that allow them to supply gas for both MIG welding or TIG (tungsten inert gas) processes.
Check all connections for any holes or gas leaks.
Generally, the shielding gas is not harmful since it is inert. That being said, if too much of the gas leaks in a confined space, damage to your lungs, including asphyxiation, can occur. To avoid these harmful effects, be sure to check the hoses, connections, and valves for any holes that could result in gas leaks.
Besides the safety concerns, you will want to make sure that none of your equipment is leaking so that you do not waste any of your shielding gas. It is simply best practice to regularly check that your equipment is in proper shape.
Open the valve on the shielding gas tank and set the rate.
After you have checked for any damage to your equipment, you can open the valve on the shielding gas bottle and insert the gas regulator into the valve. You will likely have to use a wrench to tighten the locking nut.
Turn the knob on the gas regulator to set the pressure at about 30 cubic foot hours. For most MIG welding purposes, the cubic foot hours rate will be between 20 and 30, depending on the materials, gas, and wind conditions.
Turn on the MIG welder and trigger the MIG gun.
You can turn on the welder once you have attached the gas regulator and adjusted the pressure to its initial setting. By pressing the trigger switch on the MIG gun, you activate the gas flow. As you trigger the gas flow from the torch switch, the gauge that reads the gas flow will drop to a steady reading.
Typically, the gauge that reads the overall pressure in the tank of shielding gas is on the right, and the gauge that reads the pressure that exists the tank is on the left. The gauge on the left is where you will adjust the pressure of the gas flow.
Set the gas to the proper flow rate.
While the particular circumstances will determine the exact rate of cubic foot hours that you will need to set the shielding gas pressure to, the most common flow rate is about 20 cubic foot hours.
You may need to adjust the gas pressure more than once during any single welding session. An outdoor wind or even the breeze from a fan can require you to make adjustments to keep the gas pressure at the correct level.
Frequently Asked Questions About MIG Gas Flow
Whether you are new to MIG welding or have plenty of experience, you will likely have questions about the process at some point or another. Here are a couple of common questions and their answers.
Why Does Shielding Gas Matter in MIG Welding?
It is not difficult to understand why you would want to properly adjust the pressure of the shielding gas on your MIG welder when it comes to preventing gas waste. It is a little harder to understand how improper gas pressure can affect the quality of your welding, however, unless you have actual made the mistake of not adjusting the gas pressure.
The purpose of shielding gas is to protect the weld puddle, which is molten, from atmospheric gases. Gases in the atmosphere can make your welding have increase porosity, which is basically miniscule holes and imperfections in the material.
Higher porosity in your welding can not only make your welding’s quality look less professional, but it can also weaken the overall weld. Those microscopic imperfections can seriously weaken your weld and cause structural damage.
You should also remember that one of the main goals of using a shielding gas is to keep atmospheric gases, such as oxygen, from entering the metal materials before they cool, meaning while they are still molten.
How Does Shielding Gas Work?
In MIG welding, a metal wire comes from the welder through a cable to the welding torch. This wire’s positive charge arcs it to the work piece, and the electrical circuit generates heat that melts the wire and area of the work piece.
This fuses the wire and work piece together. The shielding gas creates a cloud that the electrical arc takes place in. Shielding gas is nonreactive, which stabilizes the electric arc. Through this stabilization, other atmospheric gases are prevented from entering the arc.
This is why it’s so important to get the shielding gas flow just right.
Final Thoughts: The Gas Pressure Matters
Hopefully, you can now appreciate the importance of knowing how to adjust the pressure of shielding gas when you are doing any sort of MIG welding work. While the process is relatively simple, it is a crucial concept to know.