MIG welding is not a one-size-fits-all process. There are so-called “all around” MIG, sure, but there are times when it’s best to use a specific type for specific situations and environments, not to mention a specific skill-set.
It is not rocket science, but that doesn’t mean you can just wing it and hope you can good results. If you want to do it right, you need to use the proper tools and execute the right techniques.
Speaking of proper tools, there are two types, namely Gas MIG Welder (also called “Gas shielded”) and Gasless MIG welder (also called “Self-shielded”).
Yes, it MIG without gas is possible, and we’ll go through everything you need to know. It is sometimes called no-gas MIG.
Best gasless welder machines & wire
Simply looking for recommendations on the best gasless welders to get you started on your projects? We’ve carefully reviewed the options on the market to bring you the best contender in each category, as well as providing you with the best gasless MIG wire.
Gas vs. Gasless MIG Welders: What are their differences?
Do you need gas for MIG – is it really required?
One major difference between the two is that one uses an external shielding gas while the other piece of equipment doesn’t. Can you guess which is which? This shield is used to protect the material from contamination and oxidation caused by exposure to the atmosphere. There are many ways for welders to generate this, but most use a cylinder to pull it off. Let’s take a closer look at the craft of doing it without gas!
The gasless welder, on the other hand, uses a self-shielding wire (also called “Innershield wires”), a metallic tube filled with flux core. Once heated, this wire causes the flux to melt, producing a “shield” that will then prevent the material from being oxidized and contaminated. The melted flux also produces a protective slag that integrates alloys into the metal, which produces its mechanical properties.
(Note: It bears noting that this equipment is not really “gasless.” People have simply started calling them that because self-shielding wires don’t need a cylinder. With that said, we’re still going to use the term for the sake of those who prefer to use the term.)
Self-shielding wires have other benefits besides protecting the work from oxidation and contamination. They also generate an intense arc that can be used on steel, specifically those thinner than 1.2 mm.
Another major difference between the two are their polarity settings. “With shielding” gas MIG uses a single positive torch feed while gasless MIG uses a negative torch feed. However, in cases where the trigger is what drives the relay, polarity won’t matter at all. That said, some machines can operate in both modes, and thus provide users the option to change the polarity of the torch based on the needs of the job. Of course, those that can use both modes are more expensive, and that’s not even counting the upgrade kit that’s always required for “with gas” applications.
Gasless MIG is becoming popular in industrial settings for many good reasons. For one thing, using it means that companies don’t have to rely on shielding gas anymore, helping them save up on costs, not to mention help them do away with storage issues at the jobsite.
Moreover, using it eliminates the expenses that would have otherwise been spent on tents or wind shields that are typically used to protect welds from the atmosphere.
Companies whose employees are used to Stick, however, have to conduct the necessary training to help them properly employ the techniques and attune themselves better to the process. It also bears noting that the guns used for self-shielded MIG welders are also different from those used in Stick, and as such require you to work at different angles and postures. If the techniques aren’t executed properly, slag is likely produced. That’s why it’s important that you constantly check for the presence of spatter and debris in between passes. If you don’t, your wire feeding will be compromised, resulting in poor results.
When doing gas MIG, it’s ideal that you begin with the electrode far away from the weld, and then allowing it to inch closer as the rod melts slowly during the process. It’s different with gasless, in which you have to maintain the same position throughout the process. In this scenario, the recommended distance between the contact top to the weld is at least a half inch.
Pros and Cons: Is It Any Good?
Now that you know their differences (and similarities), you’re probably wondering which to go for. To help you arrive at an informed decision, let’s go over the pros and cons of each type.
Here are the advantages of using a gasless MIG.
It’s more convenient
When picking the right equipment, it only follows that you pick the one that is most convenient to use. In terms of convenience, the equipment has the advantage over its counterpart type of equipment. Firstly, these machines are much more compact and lightweight, making them easy to carry. It doesn’t hurt that you don’t need to clean the material prior to starting.
Moreover, self-shielded flux-cored wire is better suited for surfaces that are rusted or painted over. Why? Because the flux used in such machines allow the tool to fuse through rust and paint easily. It’s for this reason why they are becoming the tools of choice in industrial settings.
It’s great for outdoor work
You might want to go for this type if the bulk of your jobs will be done outdoors. Why is it better than “with gas” MIG welders? Firstly, it uses a shielded gas, which tends to be blown away easily when exposed to windy weather. This causes the bead to become porous, which can compromise the quality of the bond. With self-shielded MIG equipment, you can work to your heart’s content in windy weather and not have to worry about your material getting contaminated or oxidized. If you’re a craftsman who’s always on the move, using this equipment is the way to go.
It’s got better arc control
If paired with voltage sensing wire feeders, it can give you increased control of the arc, allowing for cleaner, smoother, and more precise work. Given the proper filling materials, MIG that uses self-shielded flux-cored wire can be an “all-position” method.
It’s easier to use
Training with this method is relatively easy, especially if you compare it to a method like TIG. Because you don’t have to rely on high-strength pipes, you don’t have to keep monitoring a wide range of parameters.
It is faster
Unlike with stick electrodes used in gas welding, it has much greater deposition efficiency, which means less filler material needed to complete the job. If speed is of the essence (and given that you can maintain the quality), using this type of machine can help you get the job done in less time.
There are also some disadvantages. If any of these disadvantages are a deal breaker for you, then you’re better off using another type of hjtechnique.
Positioning is limited
To do the method hright, you are relegated to limited positions. This makes overhead or vertical work very challenging. While working in these positions can be done, it takes some getting used to.
Production of fumes
They don’t have flux coating that can cause the material to solidify faster. In other words, they don’t have a covering that holds the molten pool, which is important when you’re working in an overhead or a vertical position. As a result, toxic fumes are more likely to escape, which can compromise your health upon exposure. No surprise there. After all, fumes contain Argon, nitrogen, carbon monoxide, carbon dioxide, and hydrogen fluoride. According to OSHA, short-term exposure can result in nausea, dizziness, eye irritation, and kidney damage. Long-term exposure to such fumes can also result in cancer.
Switching on Over to this Type? Mull on these Facts
Have you decided to switch to self-shielded MIG welding? Great! But not too fast. While switching is often a good choice, there are specific considerations you need to think over and measures you need to take to ensure that the transition goes smoothly. Here they are.
Compliance to codes
Before you switch, you need to be aware of the structural codes by the D1 committee of the American Welding Society (AWS). More importantly, you need to make sure that you’re complying with those codes.
Furthermore, you need to check if there are additional certifications you need to complete for specific tasks. If you already have certifications, it’s important that you get them requalified with the new procedures in mind. With that said, it’s ideal that you undergo requalification on a regular basis to ensure that the process is fast and efficient.
Choosing the right equipment
Choosing the right flux core or the best MIG welder is critical when you start this new type of craft. Considering that self-shielded FCAW requires a constant-voltage power source, you need to maintain the recommended voltage throughout the process. If your equipment isn’t able to maintain a steady voltage, mistakes or irregularities (porosity for instance) are to be expected.
Selecting the correct wire
For self-shielding to work, you need to use the correct wire, particularly the self-shielded flux-cored wire. It has different seismic requirements and requires the appropriate strengths, not to mention that the wire you’re using needs to have the chemical and mechanical properties that can accommodate the structural applications required for the job.
While it is easier than most processes, it has its attendant challenges that need to be addressed. Here are the key practices that will bolster your success with self-shielded flux-cored welding.
Maintain the right travel speed and angle
When performing work in the vertical position, aim your gun at an angle of 5 to 15 degrees. When working in a flat or horizontal position, make sure that the drag angle is 15 to 40 degrees. Maintain your speed as slowing down can cause the piece to puddle, which can result in the production of slag.
Maintain correct heat input
You need to maintain proper heat input to ensure that the metals fuse well. To pull this off, use the voltage recommended by the manufacturer relative to the wire diameter. Slag inclusions are likely to occur if you don’t provide enough heat.
Clean the material thoroughly in between passes
By cleaning the surface of the base metal thoroughly between passes, you can remove contaminants that may cause fusion issues. You can remove any slag by using a chipping hammer or a wire brush.
Maintain the right penetration
Maintain the right penetration by monitoring how much metal is being deposited to the joint within a given time period. You need to ensure that there’s enough space between the bead and the joint for the metal, especially when you’re making root passes and maneuvering through wide openings.
If you go too deep, the metal will penetrate through the base metal and hang from the underside. To prevent excessive penetration, reduce the voltage range to the recommended settings and slow down the wire feeding. If it’s the other way around (lack of penetration), turn up the wire feed speed and increase the voltage range. It’s also a good idea to set up the joint so as to make the groove’s bottom more accessible without losing your hold on the wire extension and the arc.
Prevent porosity and wormtracking
Porosity in metal is not pretty too look at, and you’d do well to do the proper measures to minimize it. One good way to prevent porosity is to use filler meals that contain deoxidizers. Also, double check that the wire stick-out (the wire’s extension length from the gun’s nozzle) is not 1.¼ inch apart from the contact tip.
Another common issue with MIG is the incidence of wormtracking, which are marks made on the bead’s surface due to the fumes released by the wire once the flux has melted off. You can prevent this from happening by maintaining the recommended voltage settings for the wire feed. If you spot signs of wormtracking, the best course of action is to turn down the voltage by increments of 12 volts until the issue is fixed.