When you are forced to lug around a gas cylinder many welders naturally consider the viability of welding without gas. It is technically possible to MIG Weld Without Gas, but there is a specific approach, and some welding supplies are required. Any larger MIG welding projects will require gas, but for smaller repairs or home projects, you can avoid using gas.
This is a simple way to weld, and you can save money at the same time. The technical term for this is Flux Core Arc Welding (FCAW), but most welders refer to this as “Flux Core” welding. FCAW uses “flux core welding wire” which is consumable, and it functions in a similar manner as the MIG electrodes.
Why Do MIG Welders Need Gas?
MIG is an acronym for Metal Inert Gas and as such it’s implied that gas is required to weld. The shielding gas is used to prevent the contamination of the molten weld joint when it meets the air. But the aforementioned FCAW approach can work for smaller projects and to make basic repairs.
What You Need for MIG Welding Without Gas
During MIG welding, a gas shield is required. Technically speaking, it’s not strictly true that MIG welding is occurring if no gas is used. But, to carry out “MIG welding without gas” there are four preparations to make.
1. Flux Core Wire
First, you will need a special flux core wire that allows you to weld without using gas. The wire is shielded as the flux is transformed into gas when the wire is melted. This is a simple procedure and you will not need a cylinder of gas for FCAW welding.
2. Setting the Welder Polarity
When you work without gas, it’s important to set up the polarity of the welder with negative electrode and positive earth. This will supply more power to melt the wire evenly and efficiently. If the wire is not hot enough, it will not create the localized gas required for FCAW welding.
3. Be Prepared for Slag and Splatter
When you carry out FCAW welding, there tends to be some slag crust and weld spatter on the top of the weld joints. The slag forms as a protective bubble coating and you cannot see the weld pool. This is a common problem encountered when FCAW welding with no shielding gas is used.
The results can be improved with practice, adjustments to the speed and improving your technique can help. Moving the torch in a zigzag movement can prevent the arc from dipping into a cooling weld pool. During FCAW, the arc is stable, but slag can block the arc anyway and the crust can be removed with a wire brush. Clean the area before you begin and take care to avoid brushing at the extreme edges of the weld for better results.
4. Carefully Choose the Corded Wire
There are a couple of corded wire variants that are not suited to FCAW. The first is a “dual shield” wire that is used to weld thicker metals together, but it lacks the gasless flux needed to make a strong joint. The second is a “metal cored” wire that has ground metal at the core which cannot be used without a shielding gas.
Considerations for how MIG Weld Without Gas
During MIG welding without gas, safety is the primary concern to avoid UV damage and burns. All the usual safety equipment must be worn and the metal surface will require brushing or grinding for a clean finish. Removing the trapped air will improve the weld quality. Choosing a powerful 115v or higher welding machine with sufficient preheating times will make the FCAW process more efficient.
Which is Best? to MIG Weld Without Gas or With Gas?
Now that you understand more about MIG welding and FCAW it’s natural to wonder which is the best approach for specific projects. This is not an easy question to answer, every welder has a unique technique, approach and needs that are hard to define.
However, there are seven clear aspects of welding that can help you to choose between MIG and FCAW, they are:
1. Gas Cylinders and Portability Problems
There are smaller gas cylinders, but portability can still be a real problem in certain situations. Use flux core is lighter, no gas cylinder is required and this is important when you consider that a gas tank can weigh 100 lbs. If you’re working in tighter spaces and/or you don’t want to lug a gas cylinder cart around then FCAW may be the solution.
2. Welding Outdoors
When you need to weld outdoors, flux core wire is easier because it works even if the conditions are windy. The production of flux core gas is more constant and consistent if you don’t want to shield the surface from the elements.
3. The Penetration Power
Both MIG welding and FCAW work on many materials without a lot of preparation and cleaning. But MIG wires do need cleaner surfaces for efficient gas welding. FCAW provides good penetration strength on thicker materials if you have a powerful machine.
4. Welding Fumes
The FCAW process produces more fumes than standard MIG welding with gas. If you have any pre-existing breathing conditions, it’s a better idea to stick with gas. If you follow good safety and protection procedures it is possible to use FCAW with no problems.
5. The Position of Welding Application
The position where you will apply the weld can determine which is the best method. As an example: a vertical weld is easier to create with MIG gas welding. The control of the gas flow can direct the shielding gas to where you need it in any direction. This can be harder to achieve when you use MIG welding without gas.
6. Is it Easy to Use a flux core Welder
FCAW is convenient, but it’s hard to master because flux core wire is fragile when compared to solid wire. MIG welding with gas is a more straightforward approach because it’s easier to control the direction and flow of the gas.
7. Price of Welder
When you’re starting out as a welder, it’s important to keep your expenses under control to maximize your profit margins. Using FCAW is cheaper than MIG welding because you don’t need to buy external gas tanks. Quickly mastering FCAW is possible with a lot of practice on scrap metal pieces and MIG welding can be added later as needed.
MIG Weld Without Gas Frequently Asked Question’s
In summary, there are two FAQs that are easy to answer. They are:
1. Is MIG welding without gas effective?
Yes, with experience FCAW is an effective technique and it can be a real advantage when working outdoors in windy conditions.
2. Can I weld without shielding gas?
Yes, with special flux core wire the slag that is created on the top of the weld will protect the weld puddle from contamination.
MIG Weld Without Gas-In Conclusion
Although MIG is an acronym for “Metal Inert Gas” it is possible to use a powerful welding machine with special flux core wire to simulate the presence of shielding gas. In certain situations, the MIG welding without gas or FCAW method may be preferable and more convenient.