Yes, with polarity adjustment and the use of a suitable wire, you can use flux core in your MIG welder.
Understanding Flux Core Welding in MIG Machines
Flux core welding is a variant of the traditional MIG welding process, which uses a special tubular wire that is filled with flux. The flux in the core of the wire performs the same function as the shielding gas in MIG welding, protecting the weld pool from contamination by the atmosphere. Offering high welding speeds and compatibility with a variety of metals, flux core welding is a versatile option for welding products .
The Process
The flux core welding operates on the same principle as other welding processes, relying on the heat produced by an electric arc that melts the wire electrode and the workpiece metal, generating a weld pool . The flux inside the wire supports the process and melts as well, creating a gas shield around the weld pool . This shield covers the molten weld, protecting it from reacting with the oxygen and nitrogen in the air . In addition, the flux generates slag, which covers the weld bead during cooling . Key Advantages
The main advantage of this welding process is the fact that it can be used to weld through dirty and rusty materials, as the flux can handle impurities . In addition, flux core welding is much faster than any other type of welding, with speeds exceeding the welding speed of MIG welding by up to 40% . Moreover, since a shielding gas is not needed, the process becomes much cheaper in the long run . For example, in welding projects which involve the use of thick materials, the overall welding time is reduced by up to 25% compared to MIG welding.
Many MIG welders today are capable of flux core welding with minimal modifications, such as a welding wire change and sometimes a polarity adjustment. As a result, people can safely switch between MIG and flux core welding, alternating the techniques, depending on the project. The initial investment in a MIG welder that can be easily transformed into a flux core welder ranges from $400 to $2000, depending on quality, capacity, and brand. When working with wires other than the usual MIG materials, users have to consider the type, size, and spool compatibility with the welder and stick to the recommended wire types. The costs of adjusting the welder to accommodate new wire and changing the contact tip and welding gun, if necessary, can reach $50 to $150, making the conversion both efficient and affordable.
The Role of Polarity
Polarity has a significant impact on the results of welding, influencing the depth of penetration, the shape of the bead, and the quality. Flux core welding is typically performed in direct current electrode negative, or DCEN, mode, producing greater penetration into the base metal than direct current electrode positive, or DCEP. As a result, welders working with thick materials should focus on DCEN to ensure that the weld thoroughly merges multiple pieces of metal to create a solid bond. Luckily, the process of polarity adjustment is simple, requiring welders to swap the leads in the gun and the ground clamp. In this manner, the welder can reach the maximum efficiency in working with thin sheet metal and thick structural material.
Modifications for MIG Welders to Accept Flux Core
To use flux core welding processes using a MIG welder, you need to modify some of the equipment. The changes help to transform the device to better suit the characteristics of wire and procedure. Primarily, one way to do that is polarity reversal, which is more closely related to adapting the MIG welder for flux core welding.
Polarity Reversal Techniques and Tips
There are various methods and tools to use the system for flux core welding, but the majority of them requires direct current electrode negative (DCEN) , as the MIG setting by default is direct current electrode positive (DCEP) . The adjustment would allow the arc to form properly and increase penetration as well as reduce or eliminate the undercut and enhance the quality of the bead . The process costs capacity loss that is worthwhile to remember too. In addition, one needs to unplug the device while making the adjustment to ensure safety.
Common Replacement Items
The wire is different, softer than MIG wire, and differently shaped, requiring a change of feed rollers and contact tips.
Feed rollers: The replacement part is knurled rollers that feed the soft wire better and prevent the wire from slipping side to side . The price of knurled rollers varies from $20 to $50, depending on the type of the device.
Contact tips: Tips for flux core wire are larger than their counterparts for MIG processes. The difference is used to offset the factor of expansion with the wire heated. The replacement part costs from $2 to $5. Both the knurled rollers and the tips are relatively cheap and do not require significant financial input to acquire them.
What Experienced Welders Do
Many experienced welders make additional changes to the system to improve or adapt it to their styles and needs. Among them are adjustments of tension on the drive system for the wire and the disconnection of gas supplies or disabling the welding system to stop the flow of gas. These processes can also include ventilation system upgrades or installation. Ventilation systems have high individual cost, which is one of the reasons they were not mentioned in the more general list of changes. All the modifications affect not just the MIG welding process adaptions for flux core welding but also have a significant impact on the quality as well.
Pros and Cons of Using Flux Core Without Gas
Flux core welding without a gas shield has both benefits and problems that significantly affect its efficiency and result of the process. The process is ideal for outdoor works, as it is not influenced by wind that can displace the gas shield and contaminate the weld. In this type of wire, the flux in the core spoils its own shield, preventing atmospheric air from penetration. Apart from that, automatic flux tries to protect the weld using shielding gas that is added to the process, making it highly efficient outside. At the same time, the process is also much more mobile, as the welder does not have to drag around the gas tanks. This reduced time and effort for the preliminary procedure, thus reducing the total time of works. However, the welding can be less effective due to a higher level of spatter, and finding the correct depth of penetration might be complicated.
Comparing Gas Shielding vs. Flux Core Efficiency
The core difference in efficiency between gas-shielded and non-gas shielded flux core welding is the absence of the gas shield. Gas shield provides better control over the atmosphere inside the chamber, shielding more evenly and cleanly. In the case of an outdoor environment, however, the weld quality is more consistent due to eliminating the possibility of the gas beam being displaced.
Gas Shielded Welding Efficiency
Gas shield flux core welding provides excellent control over the welding process, and the lack of atmospheric air guarantees a clean and even welding. At the same time, the process is expensive necessarily, due to the need to supply and maintain the gas chamber. It also reduces the portability of the entire construction, making it less effective for use in the field. In most cases, the cleanliness of the weld, and, thus, quality, required to justify the expenses are achieved in the controlled environment. Still, welding employing the gas chamber costs from two to five times more, depending on gas prices and consumption.
Flux Core Welding Efficiency
In the case of weldings without a gas shield, importance in the efficienecy of controlled environment is significantly decreased. The total lack of control, in comparison to conventional electric arc welding, is leveled by eliminating the source of variable impact. At the same time, the additional spatter and need to clean contaminating components add to the time of work. The penetration is also more difficult to achieve with flux core welding, especially for inexperienced welders. Thus, the efficiency also depends on the skill and experience of the welder, but, in general, is higher in the long run: even though additional time is spent on cleaning, the time of gas chamber preparation is eliminated, making the welding both shorter and more effective in the field.