Common Mig Welding Mistakes – Avoidance and Quality

There is a lot that can go wrong with Mig welding. The common mistakes associated with this type of welding and how to get it right are all mentioned below. If those mistakes are taken care of, Mig welding will be easy to do. 

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Welding is an awesome skill. Not all can be able to weld and persistently stick to this career. That is why when your welders perform this kind of task, make sure they are well versed about it for their own safety and better work productivity.

For Mig welding, there is a lot that can go wrong with this type of welding. The frequent mistakes associated with Mig welding and how to get it right are all mentioned below by VMST – a veteran provider of welding manpower. 

COMMON MIG WELDING MISTAKES

• The parts to be welded have to be very clean. Dirt and paint should not be there when the parts are being welded. This is a general mistake made by a rookie welder. If the parts and the surface to be welded aren’t clean, the weld won’t be proper and a bad weld will be the consequence. 

• While Mig welding, you need use the right type of gas. Some people may tend to use cheap variety of gas. It will be cheap to just use carbon dioxide, but a mixture of gases will generate the desired result and good welding. 

• If the polarity is wrong, the weld bead that is created won’t look good. 

• The sizes of contact tip should be right. 

• The speed shouldn’t be too slow or too fast.

• During welding, the wind should be blocked and should lead to proper shielding.

• If the welding is really cool on a big piece of material, proper welding won’t take place. 

• The sizes of welding machine should be right. A very small machine for a very large material won’t do the work properly. 

• The components of wire feeders – for example, contact tips, liner and other parts should be properly maintained to give the desired result of proper welding.

• The filler material should have the right tensile strength. If this is not correctly matched, the result won’t be right. 

• When welding up a joint, some welders leave too large or uneven of the gap in between two panels that they’re joining. You may want a really small gap on some joints, but in most cases, there will be next-to-no gap between the panels when welding. Too large of a gap, then you will have trouble with the bead burning away the panel edges and enlarging the gap. 

So it’s necessary to follow some rules to get Mig welding right. 

HOW TO GET MIG WELDING RIGHT

1. Cleanliness is the King – There are times you can’t always get your work area surgically clean when Mig welding. Still, you should take every step possible to do it if you expect a clean, strong weld. Your work area should be free of all grease, rust and coatings. This can be done with a wire wheel or a grinder.

2. Set up Mig welding machine properly - It has 3 settings: voltage, wire speed feed, and shielding gas flow rate. On the interior panel of Mig welder, there will be the chart that will give you the correct setting for different materials according to their thickness. The shield gas flow rate should be protected from surrounding air. 

3. Check your polarity settings – If you’re welding with the solid wire, set your machine to the reverse polarity (DCEP – Direct current electrode positive). But if you’re welding with flux core Mig wires, you may want to use the DCEN setting (Direct current electrode negative). You should also experiment a little on some scrap metal. Indeed, you should definitely practice on scrap metal if you are not sure which setting is right!

4. Check your ground - You welder is poorly or inconsistently welding, even after you tested your settings on some scrap metal? A chance is that you have a poor ground. Besides having as clean of a work area as possible, you need a clean surface to ground your machine. If you don’t have a good spot to clamp to, then tack weld a stud or a bolt to your work area to get a good continuous ground.  

5. Check your gas – To make a clean weld, the weld puddle needs purifying whilst it is being formed. This is where the shielding gas is brought into play. It is one of other essential keys to producing a clean weld. Make sure you have a sufficient amount of gas coming out of nozzles when welding; the amount needed can vary by the conditions that you’re welding (try to be out of such direct moving air as wind, fans, etc.) and the surfaces that you’re welding on. Mig welding can be done with machines only using flux core Mig wire though, you’re suggested to choose a Mig welder which is versatile enough to use gas as well. Welding with shielding gas is the best way to create the cleanest weld with little-to-no cleanup. 

6. Use the proper welding technique - The welding technique for all welding types is the same. People use the weave technique with a side to side motion, or the whipping technique with a back to forth motion, a circular motion. Whatever technique is used, the wire stickout shouldn’t exceed three-fourth of an inch. Otherwise, the shielding gas won’t be able to do the work properly.

7. Stickout has influence - When setting up your machine, you need make sure that you have your contact tip sticking out the right amount for the welding type you are doing. The rule of thumb is that the welding tip has less than ½" of stickout. You can get away with a bit more if you’re welding on the thinner sheet metal (body panels, etc.). Still, you need stick in that range for just about all applications. Always check your stickout each time before welding.

8. Proper joint construction – Take time to put together an even, tight gapped joint. Doing so will better the final appearance and the strength of the job. The proper joint prep can be panel holding system, intergrip panel clamps, welding clamp plier set.  

A good welding helmet helps with your final weld quality.

9. Use auto-dimming helmet – Static darkness welding helmet works ok if you’re in a really well light area or if you’re good at flipping down your helmet and striking an arc in quick motion at the same time. Still, with today's advancements in the welding accessories, it isn’t necessary anymore. Now you can find cost-efficient, quality auto dim welding helmets quite easily. Being comfortable when welding helps you better your weld quality and allows you to see your work area properly before, during and after you weld.

10. The angle matters – The tip angle when welding can also really important. Ideally, you should be straight on when you’re doing quick spot or plugging welds, whilst keeping roughly a 10 degree angle when welding with the pulling or pushing method is satisfactory.  

11. Choose the correct wire size - ‘Bigger is better’ doesn’t always hold true in this case. It is also dependent on the welding type you’re doing and the surface you’re welding on. If you’re mostly working with such thin metal as body panels of a car, you would want to use .023 solid core wire. That will allow you to keep down the temps as opposed to using a much thicker wire. And in case you didn’t know, too much heat is equal to metal warpage. Keep in mind though, if you’re doing chassis or suspension work that the metal is substantially thicker, you would want to use .30 or .35 solid core wire. This will ask for 110 machines to run at the higher end of voltage spectrum. 

12. Be safe - There are lots of hazards of welding, lots of them are pretty obvious, whilst others can be easily overlooked. Make sure you wear the proper attire when welding. That means long pants, leather welding gloves, welding jacket, closed toe shoes. Dressing properly can save you from being seriously burnt from the intense heat and light generated when welding. Also, keep in mind that you need keep your work area safe. Rather, cover or remove all flammable objects from the work area, and allow for proper ventilation from any fumes that can be generated when welding. 

13. Give regular Mig maintenance - One of easiest ways to make your Mig gun run more seamlessly is to replace the liner. A wire, oftentimes, will start to jam or at least run less smooth than before. Still, if you keep some liners handy, you will be prepared to get a new one when you need it. The loss of weld quality, loss of time on task, and the like make some investment in a new liner worth it. Also, take time to clean out spatter for the Mig gun and replace the torch tip when necessary. When you can keep a steady flow of electrode into weld puddle, Mig welding works best. 

There are lots of things that can go wrong while Mig welding though, by putting these tips into practice, you will be able to avoid some of most common mistakes that come up while Mig welding. 

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Top 12 Disadvantages of Mig Welding that You Should Know

Mig welding is a widely used arc welding process. Like other processes, it has disadvantages aside from advantages. Know well about its downsides to avoid mistakes with this process and improve weld quality and productivity.

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Despite its paybacks, Mig welding has some drawbacks that you should grasp well.

1. Sensitivity to contaminants

Mig welding process can only deal with low-to-moderate levels of surface contaminants like mill scale, rust, oil, dirt and paint. All those have potential to cause such problems as incomplete fusion, porosity, poor bead appearance, and even cracking.

2. Sensitivity to wind 

The shielding gas used for this process can be easily blown away when welding takes place outdoor. Even inside, a fan or a wind draft of 5 mph can be enough to induce porosity in welding.

3. Limited positions

High heat input of a Mig welder and fluidity of welding puddle aren’t suited to overhead or vertical welding. Whilst some welders never think of welding in one of those positions, take this factor into account when deciding whether to buy a Mig welder to ensure it can accomplish all of the tasks planned for it.

4. Lack of fusion 

Owing to the ability to weld at low currents, Mig welding has the potential for incomplete fusion welding defect when operating in short-circuit mode. Ensure you always apply the proper procedure for the thickness of material you’re welding. 

5. Portability problem

Moving the welding equipment mayn’t be that difficult though, you also have to deal with the high pressure cylinders containing the shielding gas. Proper care must be taken.

6. Open arc process 

Like most welding processes, Mig welding is an open arc process. Proper care must be taken to shield the welder and by-standers from harmful UV rays.

7. Fast cooling rates

The welded metal will cool at higher rates because they are not covered with slag when the weld is completed.

8. Shielding gas

It can take time to replace the shielding gas bottles, and they can get in the way whilst welding.

9. Time for metal preparation

Before you weld with a Mig welder, the material has to be free of dirt or rust for a good weld got and safety’s sake.

10. Difficulty getting into tight places

The gun is hard to get into tight places.

11. The equipment is pretty complex

The equipment is rather complex, since this process require a direct current source, a constant source, flow of gas, and continuously moving wire electrode. Also, electrodes are available in various sizes and made from numerous metal types to match the welding application.

12. Learning curve associated with Mig welding

As the actual technique employed is different from conventional welding practices, there is learning curve related to Mig welding, even for veteran welders. For instance, Mig welders need push the welding puddle along the seam and away from them.

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Top 16 Advantages of Mig Welding that You Should Know

Those advantages of Mig welding can reason why this process is most widely used process in many countries.

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Mig welding advantages and disadvantages are commonly determined by kind of Mig welder as well as the nature of the job. Before discussing the upsides and downsides to this process, it’s important to first clarify which Mig welder to use and where it will be used.

Mig welders comes in 1-Phase, 3-Phase and combination 1 and 3-Phase. 1-Phase Mig welders typically have a 115 or 230 VAC, and are used in farms and ranches, home garages, body shops, general repairs, small maintenance work, art work, light fabrications.

Meanwhile, combination 1 and 3-Phase Mig welders give a bit more flexibility for welding. They can finish well the same things as the 1-Phase Mig welder while they are also employed for light manufacturing and fabrication.

Once you know you will be doing the kind of work requiring a Mig welder, you will be able to assess its advantages and disadvantages. Many welding workers would argue that the upsides far outweigh the downsides.

1. Higher productivity

Many welders enjoy higher productivity as a result of time saved by not having to change constantly rods or chip away slag, and not having to repeatedly brush the weld. They are able to work cleaner and faster.

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2. Low cost equipment

You just need invest less than $600 in a welding machine from such reputable manufacturers as Lincoln Electric or ITW. Adding some dollar for shielding gas and Mig wire, you are welding for $700 or less.

3. Low cost consumables

Out of all the processes, consumables for Mig welding cost the least. Mig wire from a large box store is less than $3 per pound, and from a local industrial distributor is closer to $2 per pound.

4. High deposition rates

Especially when compared to stick welding. With Mig welding process, the deposition rates are around 10 pounds per hour (deposited weld metal).

5. Low hydrogen deposits

Unlike stick electrodes and flux-cored wires, solid doesn’t pick up moisture. That’s why it deposits welds consistently with low diffusible levels of hydrogen.

6. Can weld just about every metals

Just by changing the filler wire and sometimes the shielding gas, you can weld stainless steel, carbon steel, nickel alloys, aluminum.

7. Low levels of spatter

Low spatter can be attained by selecting right mode of metal transfer. Pulse, and spray welding can bring this benefit.

8. Unlimited thickness

Mig welding process can be used to weld light gage material and even unlimited thickness by using multiple passes. There need higher amperage and appropriate joint configuration to weld.

9. Easy to learn

Mig welding is easier to learn than stick welding or Tig welding. It takes just a few hours for welders to learn how to Mig weld, and some instructors claim that they can offer basic training in 20 minutes - with most of the time spent on cleaning the weld.

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10. Clean and efficient

Since Mig welding uses a shielding gas for the arc protection, very few alloying elements are lost as metal transfers across the arc. There isn’t slag to remove, which is common for stick welding. Also, just very little weld spatter is produced. Following a brief clean-up, Mig welders can be back on the job thanks to minimal clean-up required.

11. High electrode efficiencies

Mig process gives efficiencies of 93-97%. That means when buying 100 pounds of Mig wire, you can deposit 93-97 pounds of weld metal. Such processes as stick welding has electrode efficiencies of about 65%. This is because of loss from spatter, slag and not consuming the entire electrode.

12. Input voltages

With electric service, you can weld. Smaller machines can operate on 115 volt input. Those machines are limited to around ¼” weld thickness. Some of newer industrial machines can run anywhere from 208 – 575 input voltage on single or 3-phase circuits. Also, Mig welding machines often can run off of the portable generators.

13. Simple and good welds

Mig welding gives better visibility of weld pool. This process is simple, and auto-feed wire offers better control. With Mig welding, it is not hard to produce a great-looking weld.

14. Versatile

Versatility of Mig welding is undeniable. Mig can weld various metals and alloys, whilst operating in various ways – for example, semi, and fully automatic. Mig welding is helpful for many home welding projects. It’s also used by numerous industries. This technique is used for copper, aluminum, mild steel, stainless steel, magnesium, nickel, and lots of their alloys, and iron and most of its alloys. 

15. Faster welding speed

The continuously fed wire would keep both hands free for Mig welding, which enhances welding speed, weld quality, and overall control.

16. Can be used in thin materials

Mig welding process can be quite easily used on thin materials if properly set. GTAW can be used on thin materials, too, but in such cases as Auto Body, Mig welding wins hands down.

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Below are important Mig welding basics that welders must grasp as tightly as possible.

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Mig welding is the most popularly used of the arc welding processes, suited for everything from small fabrications, repairs to large structures, shipbuilding, and robotic welding. Mig can be applied in a wide range of materials and thicknesses. Importantly, your Mig welders grasp those Mig welding basics to serve well their work, and refine their skills in this widely used welding process to produce more qualified welds and further their career. 

What is Mig welding?

Mig (Metal Inert Gas) is also referred to as GMAW (Gas Metal Arc Welding). This is the most widely welding process in the world for various reasons. It is fast, cost effective and welders can be easily trained to create quality work.

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Gas or flux

The welding process creates extreme amounts of heat that breakdown chemicals in the air into smaller molecules. Those substances then can contaminate the weld. 

The process generates a small electromagnetic field, which can also contaminate the weld. Weld contamination may (not) be visible to naked eye after the weld is finished. That’s why the weld can fail or show failure signs at a later time. Welders have 2 options to control contamination – use a flux core wire or use gas.

Using gas requires welders first source a welding supply or gas supply house for proper mix of gas provided, which is commonly a mix of CO2 and Argon for Mig welding carbon steel (also, mild steel).

Flux core welding wire includes a shielding substance for weld protection. Better portability is the advantage here, because there is no heavy gas rank to drag around with the welder. The disadvantage is the mess, since flux core welding often leave more spatter.  

Mig welding on mild steel and on aluminum

Mig welding can be applied for most types of metals – steel, stainless steel, and aluminum. Still, welding aluminum is far from similar to welding mild steel, as aluminum is different from steel. Then when welding aluminum, welders have to use other settings and other parameters. For instance, as aluminum has lower melting temperature than mild steel, welders should use a higher local heat input but faster welding speed than with steel for good fusion and penetration. The welding sets would automatically adjust welding parameters, then the welder can focus on the welding operation, movement of welding gun and weld pool.

The machined-controlled parameters are, for instance, wire feed speed, arc voltage, gas consumption, wire diameter. Still, even if they are machine controlled, welders have to feed them into machine before starting to weld. During the welding process, the welding set can adjust relationship between those parameters. If they are set correctly, welders just have to focus on length of stick-out, angle of welding gun and welding speed. Then in many ways, Mig welding process is easier than metal arc welding.

Mig welding can be used with numerous metals, but there are some differences that welders should beware. Mig welding on mild steel and aluminum is a good example. The biggest differences between those 2 welding methods are choosing shielding gas and levels of ampere and voltages. Also, of course, the method used for metal transfer. Types of transfer can be listed as spray arc transfer, pulsed transfer, and dip transfer (also, short arc).

The spray arc transfer has higher arc voltage and amperage that short arc transfer. It is typically used on materials of different properties and thicknesses.

Shielding gas is chosen depending on metals to be welded. When welding aluminum, welders often use a mixture of argon and helium, or argon. Meanwhile, welding steel needs CO2. 

One problem with welding aluminum is to be able to see whether the weld you are doing will be right. Often, this problem can be handled by watching the welding pool. You can see from the material penetration, and from the weld flow, whether the welded joint is Ok or not. You can see whether the amperage and voltage levels are set right, or if the amperage is too low. That is something you can learn from experience.

One of most significant factors when welding is the current level. Without the current right, welders can make mistakes when Mig welding aluminum than when welding with coated electrodes. It is also important to clean the prepared joints. They can be cleaned with stainless steel wire brush, cleaning fluid. The fluid is, indeed, alcohol. It smells terrible. Still, welders can use welding masks with fresh air supply and use them when cleaning and welding. 

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Safety first

Mig welding has very specific safety issues as compared with other processes. Following is basic safety equipment needed:

• Welding helmet with the shade 10 or 11 lens reliant on the voltage welded with for eye protection from UV radiation.

• Safety glasses to protect welder’s eyes from sparks as well as flying spatter from cleaning the weld.

• Leather gloves to insulate the welder from electric shock and burns from sparks and heat. In some cases, welding gloves come with a reflective coating to tackle the head of welding heavy plate.

• Long pants and sleeves made of cotton, leather or fire retardant material to protect the welder’s skin from UV rays as well as hot metals. Good sun block also helps the skin areas without clothing.

• Leather booths to protect the welder’s feet from sparks and molten metals that will fall.

• Good ventilation to get rid of shielding gasses but not take them away from the weld area.

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