- 2. Hold Your Hands High, Elbows Low & Move Your Head
Flux core MIG welding is one of the most popular welding techniques, used by both novice and professional welders alike. Its versatility, portability, and ability to weld in outdoor environments make it ideal for a wide range of projects. However, as with any welding technique, there are common mistakes that even experienced flux core MIG welders can make. These mistakes can affect weld quality, increase the risk of defects, and even compromise the safety of the weld. In this blog, we’ll discuss the most common flux core MIG welder mistakes and provide actionable tips on how to avoid them.
1. Not Using the Right Type of Flux Core Welding Wire
The Importance of Choosing the Right Wire
One of the most fundamental mistakes flux core MIG welders make is choosing the wrong type of flux core welding wire. The wire you select will depend on the material you’re working with, as well as the type of weld you need to make.
For instance, if you’re welding on steel, a general-purpose flux core welding wire such as E71T-11 is a good choice. However, for aluminum welding, using an aluminum flux-cored welding wire is crucial. This wire is specifically designed to weld aluminum and its alloys and will ensure a cleaner, stronger weld.
How to Avoid This Mistake:
Always match your welding wire to the material being welded. For steel, go for carbon steel flux core welding wire, and for aluminum, use the correct aluminum flux cored welding wire. Take time to read the packaging or manufacturer’s instructions to ensure you’re using the right wire for your specific welding application.
2. Incorrect Wire Feed Speed
The Role of Wire Feed Speed in Weld Quality
Another common mistake is not setting the correct wire feed speed. If the wire feed speed is too high, you may experience excessive spatter, weak welds, or inconsistent weld penetration. On the other hand, if the wire feed speed is too low, the arc will be unstable, resulting in poor fusion and a high risk of cold lap or lack of penetration.
How to Avoid This Mistake:
Before you start welding, always adjust the wire feed speed according to the thickness of the material you’re welding. A good rule of thumb is to use the manufacturer’s recommended settings for wire feed speed but be prepared to fine-tune it based on your specific welding needs. Ensure that the wire is feeding smoothly and consistently to avoid erratic welds.
3. Improper Voltage Settings
Understanding the Importance of Voltage Settings
Voltage settings are crucial in flux core MIG welding because they determine the arc length, heat input, and overall weld quality. If the voltage is too low, you’ll get insufficient heat, which will lead to poor penetration and weak welds. Conversely, too high a voltage will result in excessive heat, causing burn-through, a lot of spatter, and excessive wire consumption.
How to Avoid This Mistake:
Refer to the welding machine’s manual to set the recommended voltage for your specific wire type and material thickness. If you’re unsure, start with the middle setting and adjust from there based on the appearance of the weld. Keep a steady pace while welding to maintain a consistent arc and prevent heat distortion.
4. Not Maintaining Proper Stickout
What is Stickout and Why It Matters
“Stickout” refers to the length of the welding wire that extends from the contact tip of the MIG torch. If the stickout is too long, it will result in an unstable arc, excessive spatter, and poor penetration. On the other hand, a short stickout can lead to overheating the contact tip, causing it to wear out quickly.
How to Avoid This Mistake:
The ideal stickout should be around ½ to ¾ inch for flux core MIG welding. Adjust the length of the stick according to the material thickness and the wire you’re using. Keeping the stick out within the optimal range will ensure a smooth, consistent arc and high-quality welds.
5. Welding at the Wrong Angle
The Impact of Welding Angle on Weld Quality
Welding angle can significantly impact the quality of your weld. If the angle is too steep or too shallow, it can lead to poor penetration, weak welds, or an inconsistent bead. A typical mistake is using too much of an angle when working with flux core MIG welding, especially when welding in tight spaces.
How to Avoid This Mistake:
Maintain a consistent travel angle of around 15 to 20 degrees from vertical, depending on the material and the type of joint you’re working with. For flat welds, the angle should be minimal, while for overhead or vertical welds, the angle might need to be adjusted slightly. Ensure the nozzle is pointed directly at the joint to minimize spatter and achieve a smooth bead.
6. Incorrect Travel Speed
Why Travel Speed Affects the Weld
Just like with wire feed speed, the speed at which you move the MIG welder along the joint is crucial for achieving a quality weld. Moving too quickly can result in poor penetration and a cold weld, while moving too slowly can cause excessive heat input, leading to burn-through, warping, or an overly thick bead.
How to Avoid This Mistake:
Practice your technique and adjust your travel speed based on the material thickness and welding position. Keep a steady pace, allowing the welding wire to feed into the weld pool evenly. Pay close attention to the appearance of the bead—if the weld is too thin, slow down; if it’s too thick, speed up.
7. Not Cleaning the Workpiece Properly
The Importance of Surface Preparation
Welding on dirty or rusted surfaces is a common mistake that can lead to contamination, porosity, and weak welds. Oil, grease, rust, mill scale, or paint can all affect the weld’s ability to bond properly to the base material, resulting in defects and poor-quality welds.
How to Avoid This Mistake:
Always clean the workpiece thoroughly before welding. Use a wire brush, grinder, or chemical cleaner to remove rust, grease, and other contaminants. For aluminum, ensure the surface is completely free of oxidation. Cleaning the surface ensures that the flux core welding wire will melt and bond with the base metal properly, resulting in a stronger, more reliable weld.
8. Not Using Proper Safety Equipment
The Importance of Safety Gear
While this might seem like an obvious mistake, many welders still overlook the importance of using proper safety gear. Flux core welding produces intense heat and dangerous UV rays, which can cause burns, eye damage, and respiratory issues. Additionally, the process generates harmful fumes, especially when welding with certain materials.
How to Avoid This Mistake:
Always wear the appropriate personal protective equipment (PPE), including a welding helmet with a proper shade, flame-resistant clothing, gloves, and a respirator if necessary. Ensure that your work area is well-ventilated to prevent the buildup of harmful fumes. Safety should always be a top priority, especially when working with flux-core MIG welders.
9. Not Adjusting for Wind and Outdoor Conditions
The Challenges of Outdoor Welding
Welding outdoors or in windy environments can cause flux core welds to suffer. The wind can blow away the shielding gas that protects the weld pool, resulting in oxidation and poor-quality welds. Even though flux core welding does not require shielding gas in the same way that MIG welding does, wind can still cause problems with wire feed and arc stability.
How to Avoid This Mistake:
If you’re working outdoors, use a welding screen or tarp to block the wind from affecting your weld. Position your welder in such a way that the welding area is shielded from gusts, and always check the stability of the arc during windy conditions. This will help ensure the best weld quality regardless of external factors.
10. Welding in the Wrong Position
The Effect of Welding Position on Quality
The welding position plays a crucial role in determining the outcome of your weld. Most flux core MIG welders are accustomed to welding in the flat position, but it becomes trickier when working in vertical, horizontal, or overhead positions. In these challenging positions, the weld pool can drip, and controlling the weld becomes more difficult.
How to Avoid This Mistake:
When welding in vertical or overhead positions, you need to adjust your technique. For vertical welding, a weave pattern is often employed, moving the weld puddle back and forth in a controlled manner. For overhead welds, reduce the wire feed speed slightly to avoid excess material falling. Practice in different positions to become more proficient at welding in all orientations.
11. Not Using the Correct Polarity
Understanding Polarity in Flux Core MIG Welding
Polarity refers to the direction of current flow in the welding circuit. Flux core MIG welders typically operate on either direct current electrode negative (DCEN) or direct current electrode positive (DCEP). Using the wrong polarity can cause welding issues, such as excessive spatter, poor penetration, and inconsistent bead appearance.
How to Avoid This Mistake:
Ensure you’re using the correct polarity for your flux core MIG welding wire. For most flux core wires, DCEN (straight polarity) is the preferred option, as it offers better penetration and a smoother weld. However, certain wires, such as some aluminum flux-cored wires, require DCEP (reverse polarity). Always check the manufacturer’s specifications to ensure you’re using the right polarity for the material and wire type.
12. Overusing or Underusing the Heat Settings
The Role of Heat in Flux Core MIG Welding
Temperature control is essential in flux core MIG welding. Too much heat can cause burn-through and excessive spatter, while too little heat results in weak penetration and an inconsistent weld. Many new welders struggle to find the right balance, often overcompensating with excessive heat, especially when they want the weld to fill in quickly.
How to Avoid This Mistake:
Make sure your heat settings are in line with the material thickness you’re working on. For thinner metals, lower heat settings should be used, while thicker materials will require higher settings. Start with the manufacturer’s recommendations and adjust based on your specific welding conditions. Pay attention to the visual cues—if the weld is too thin or has visible burn-through, adjust the heat accordingly.
13. Not Checking the Gas Flow (If Applicable)
Why Gas Flow Matters in Flux Core Welding
While flux core welding typically doesn’t require shielding gas, certain types of flux core wires (such as dual-shield or gas-shielded wires) do require gas for optimal performance. Not checking the gas flow or using an incorrect shielding gas mixture can lead to poor weld quality and increased spatter.
How to Avoid This Mistake:
When using a gas-shielded flux core wire, ensure that your shielding gas flow rate is set correctly. Typically, a flow rate of 15-20 CFH (cubic feet per hour) is ideal but always refer to the wire manufacturer’s instructions for the recommended settings. If you’re welding outdoors, be mindful of wind that could disrupt the gas shield, and consider using a windbreak to maintain consistent gas coverage.
14. Not Practicing Enough
The Importance of Practice in Flux Core MIG Welding
Flux core MIG welding, like any welding technique, requires consistent practice to develop the necessary skills. One of the biggest mistakes welders make is not spending enough time honing their craft. While it’s easy to think that all you need is a welder and some wire, developing the right technique takes time, and mistakes can be costly.
How to Avoid This Mistake:
Set aside time to practice regularly, particularly with more challenging materials and positions. Start with simple welds on flat surfaces before moving to vertical or overhead positions. Practice different patterns, wire feed speeds, and angles to become more adaptable to various welding scenarios. You’ll find that the more you practice, the more consistent and confident your welds will become.
15. Not Using the Right Techniques for Thin Materials
Challenges of Welding Thin Materials
Welding thin metals with flux core MIG wire presents unique challenges. Thin materials are more prone to burn-through, distortion, and warping. It can be tempting to use a high heat setting or fast travel speed to weld quickly, but this often leads to poor results.
How to Avoid This Mistake:
When welding thin materials, always use a lower heat setting and slower travel speed. Additionally, consider using a smaller diameter flux core welding wire for better control over the weld pool. Focus on making a clean, consistent pass without allowing the heat to accumulate excessively in any one spot.
16. Ignoring the Importance of Joint Fit-Up
The Impact of Poor Joint Fit-Up
A common mistake welders make is not paying enough attention to the fit-up of the joint. If the joint has gaps, misalignment, or improper beveling, it can affect the quality of the weld and lead to defects such as lack of penetration, cracks, or insufficient strength.
How to Avoid This Mistake:
Before you start welding, ensure that the joints are properly prepared. Check the alignment, clean any rust or debris, and ensure that the edges are bevelled if necessary. Proper fit-up helps the flux core welding wire flow smoothly and evenly, ensuring a solid bond between the base materials.
17. Not Maintaining Your Equipment
The Importance of Proper Maintenance
Even the best flux core MIG welders are prone to wear and tear, and neglecting regular maintenance can lead to performance issues. One of the most common mistakes is not cleaning or maintaining the welding machine and its components. Over time, contact tips, nozzles, and the gun can accumulate debris, and this will interfere with your welding process.
How to Avoid This Mistake:
Perform routine maintenance on your welding machine, including cleaning the contact tips, replacing worn nozzles, and ensuring the wire feed mechanism is functioning smoothly. Periodically check for gas leaks, especially if you are using a gas-shielded wire. Keeping your equipment in top condition will extend its lifespan and ensure consistent, high-quality welds.
Conclusion
Becoming a skilled flux core MIG welder takes time, effort, and attention to detail. Avoiding these common mistakes is key to improving your welding skills and producing high-quality welds. By choosing the right flux core welding wire, adjusting your settings properly, maintaining your equipment, and practicing consistently, you’ll be well on your way to mastering the art of flux core MIG welding.
Remember, every welder makes mistakes, but with the right knowledge and techniques, you can minimize these errors and ensure your welding projects are successful.
If you’re ready to take your welding skills to the next level, consider enrolling in KWI’s welding programs. Our expert instructors will guide you through every step of the process, ensuring you’re prepared for real-world welding challenges and helping you become a professional flux core MIG welder.
