One of the easiest welding techniques to learn is MIG welding. As a matter of fact, this welding technique is one of the most important skills that any beginning welder has to master. Learning how to weld like a pro is easy if you know the basics of MIG welding.
Understanding the Basics of MIG Welding
While this technique of welding is easy enough, it is very important to understand a few MIG welding basics.
MIG stands for Metal Inert Gas. An inert gas is an element that is free from undergoing chemical reactions like hydrolysis and oxidation reactions. They are stable, allowing them to retain their chemical characteristics regardless of the other molecules present around them.
So, what is MIG welding? It is a type of welding process that uses an electric arc to form a short circuit between two metallic surfaces. On one end of the short circuit is a welding gun that contains an electrode wire. Welders call this the anode or the positive end. On the other end of the short circuit is the metal that the person intends to weld. It’s called the cathode or the negative end. This electric arc heats up the metal that you’d want to weld and the wire electrode. This causes them to melt, allowing them to fuse together.
The inert gas we mentioned above creates a gas shield around the weld pool. The welding gun emits the inert gas at the same time that the tip creates an electric arc with the metal workpiece. The shielding gas helps protect the weld bead from potential contaminants in the air.
MIG welding is not a new technology, however. Engineers developed the technique sometime in the 1940s to help them weld non-ferrous metals like aluminum. Today, the technology is already referred to as the Gas Metal Arc Welding or GMAW.
Industries prefer MIG welding techniques over others because of its versatility and speed. It is also very easy to adapt to more modern processes that utilize robotic technologies.
While MIG welding is versatile, people limit its use indoors where there is no moving air. Using it in outdoor applications can expose it to different contaminants where the inert gas may prove ineffective in protecting the weld pool. For example, dirt and dust can still get into the weld pool despite the presence of the shielding gas.
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MIG Welding Equipment
Before you start learning how to use a MIG welder, it is best to get acquainted with the different components of the equipment first.
- Welder
This part of the MIG welder is where you can find the spool of electrode wire necessary for creating the anode. There are also rollers that serve to push the electrode wires to the welding gun. There is a tension nut that keeps the electrode wire spool in place. You can consider the welder as that part of the MIG welding equipment that houses the wire. If you cannot advance the wire, then there is a chance that it got stuck in the welder.
- MIG Wire
One of the most critical components of the MIG welding equipment is the wire. There are different types of wires that you can use, depending on the metal workpiece. For example, if you are going to weld stainless steel, you may use ER308L. If you are welding carbon steel, then an ER70s-6 wire is more appropriate. Welding aluminum may require ER4043 or ER5356 wires, depending on the grade of the aluminum.
The size of the MIG wire matters, too. A 0.23-inch wire is good for welding sheet metal that are as thin as 24-Gauge; although they can also work in 16-Gauge sheet metal. A 0.3-inch wire is ideal for sheet metal with a thickness of not more than 1/8 of an inch. A 0.35-inch wire is good for 1/8- to ¼-inch thick sheet metal. A 0.45-inch wire is ideal for any metal that is at least a quarter of an inch thick.
- Welding Gun
If you’re going to learn how to use a MIG welder, you should focus on the welding gun. How you control the different settings of this device can spell the outcome of the weld. How you hold it also matters. Different manufacturers have different designs of a welding gun. Some come with a pistol-like grip, while others are more like an ordinary baton. Regardless, the gun has a few basic components that you should be familiar with.
First, there’s the trigger. This controls the flow of electricity as well as the electrode wire feed. There is also a replaceable copper tip. This guides the electrode wire. They are replaceable so you can use a certain size of electrode wire. For instance, there are tips for a 0.23-inch wire and another for a 0.45-inch wire, and so on.
There is a protective layer covering the outer surface of the tip. These can be made of metal or ceramic. It protects the electrode wire while also directing the flow of inert gas.
- Gas Tank
A MIG welder will not be complete without the source of the inert gas. This is where your gas tank comes in. There are three types of gases used in MIG welding.
Pure Argon is perfect for working with aluminum and other non-ferrous metals. It is a noble gas that has low thermal heat conductivity. As such, it will only create a narrower weld bead. If you are going to use this on steel, it may not be able to give you the strength of a weld that you are looking for.
Carbon dioxide is a more popular gas MIG welding than 100% Argon. You can use it on steel and other ferrous metals. It is also cheaper. The problem with carbon dioxide is that it does not give you a more stable electric arc. This causes spattering in the final weld.
The best gas for MIG welding is a combination of CO2 and Argon. It gives you a more stable and more appropriate size of the electric arc. Argon mix can also guarantee better penetration, able to weld almost all kinds of metals. Best of all, it addresses the spattering issue with carbon dioxide gas.
- Ground Clamp
The last component of the MIG welding equipment is the ground clamp. This completes the “short circuit” between the electrode wire and the metal workpiece. The ground clamp clips into the metal workpiece. If not, you can clip it in a metal welding table. Always remember that the ground clamp should always make a connection with the metal you’re trying to weld.
Using the MIG Welder
Now that we’re done with the MIG welding basics, let us now focus our attention on the actual process of MIG welding.
- Safety First
There are several things that you should always protect yourself from whenever you are MIG welding. First is the gas. The welding process will always produce hazardous fumes. You are not supposed to breathe in any of these fumes. You should always weld in an area with adequate ventilation. Moreover, you should always wear a respirator or a mask.
Second, there is the electricity that you have to contend with. It is important to ensure that all of your connections are intact. Check the power cord of your device to see if there is fraying or none.
Third, the electric arc will produce a very bright light. This can damage your eyes if you do not use the correct welding mask. If you are going to work in an area where there are other people, make sure that you also have a welding screen.
Fourth, the idea about welding is to melt the metals first. When they start to cool, they will join together. It is not uncommon for molten metal to splatter off from the workpiece. As such, wearing leather gloves is important. This material not only protects you from the heat. It can also protect your skin from the harsh UV light from the electric arc. Do not use rayon and polyester. If the molten metal gets in contact with these materials, they also melt. If you don’t have leather, cotton is the next best material.
The same is true for your feet. Always wear safety shoes made of leather. You do not want any of that molten metal splattering onto your feet or toes.
Fifth, fire is always a threat when it comes to welding. Grinding sparks and molten metal can reach combustible materials like paper, plastic bags, or sawdust. These can catch fire. Always work in a well-ventilated and clean area free of fire hazards. Have a fire extinguisher ready, too.
- Surface Preparation
In learning how to weld, it is important to prepare the metal you are going to work on. Clean it well. Smoothen the edges of the metal pieces that you want to join. This will help remove any surface imperfections and allow for the more effective welding of the two pieces.
If you are going to work with thicker sheet metals, it is best to bevel the joint. This will help guarantee that the weld will penetrate deep into the base metal. This is especially the case for butt joints.
- Set Up the Machine
Now that you’ve prepared the metal, it’s time to set up your equipment. Always check your cable connections. Check your welder and see if the polarity is set to DC electrode positive or DCEP.
Next, set the appropriate gas flow. In most applications, you will need a gas flow rate of about 20 to 25 ft3/hr. Make sure that there are no leaks in the hose. If you are not sure, then you can apply soapy water over the hose and its connections. Check if there are bubbles. The presence of bubbles suggests a leak. It is wise to replace the hose before you start welding.
Check the tension on either the wire spool hub or the drive rolls. Check your manual for the right tension settings. Always inspect your consumables like contact tips, wires, and liners. If you see signs of wear in the liners or contact tips, it is recommended to replace them. Make sure to check the electrode wire to see if it is rusty. If so, replace it, too.
- Start with Practice Beads
If you have been MIG welding for many years, you can skip this part. But if this is your first time, it is imperative that you practice first. There are many different MIG welding techniques. You can try each one to help you determine the technique that you will be most comfortable with.
There are two ways you can move the welding gun. Most MIG welders prefer to use the pushing or forehand technique. To do this, angle the welding gun at about 10 degrees with the electrode wire pointing in the direction of the weld. As you press and hold the trigger, push the gun. The advantage of this is that you will have a clear view of the joint that you want to weld.
The second method is the pulling or backhand technique. Instead of pushing the gun forward, you are going to pull it back, keeping the same 10-degree angle. This sacrifices visibility of the weld for better penetration.
Try doing both techniques before you incorporate the different weld beads. For this, the simplest type is the stringer bead. It’s a straight line that creates thin welds. You can also try the cursive “e” or cursive “v” technique. In the cursive “e” technique, you will be creating small circles that are linked to one another. This technique is ideal for thick metals. The cursive “v”, on the other hand, will create a saw-toothed or zigzag pattern. It is ideal for vertical and overhead welds.
- Get Welding
Once you are comfortable with your MIG welding techniques, you can start with your welding project. Remember to clean and smoothen the surfaces of the materials that you are going to weld.
Tips to Become a Good MIG Welder
Now that you have an idea about what MIG welding is all about, it would not surprise us one bit if you decide to become a pro MIG welder. To help you better hone your skills, here are a few MIG welding tips you can incorporate in your MIG welding activities.
- Learn to Stabilize Your Grip
In learning how to use a MIG welder, it is important that you know how to stabilize your grip of the welding gun. What you want are steady hands, not shaking or trembling. Otherwise, the weld you use will not be very pleasing to look at. Try to relax as you guide the tip of the welding gun across the metal you’re welding.
- Do Not Underestimate the Value of Cleaning Your Materials
One of the most common reasons for MIG welding failures is porosity. You would want a solid weld, not something that has pockets containing debris and other particles inside. This is why cleaning the surface of the material you are going to work on is crucial. It is important to remove dirt, oil, paint, rust, and other surface contaminants before you weld.
- Always Ensure You have a Great Ground
One of the most neglected MIG welding tips is ensuring a great ground. For MIG welding to be successful, it needs a smooth flow of electric current. Electricity always follows the path that has the least resistance. As such, if you do not place the ground clamp close enough to the electric arc, then the electric current will try to find another that is closer.
- Keep the Wire Stickout Short
If the electrode wire that sticks out from the tip of the welding gun is too long, the shielding gas may not protect the arc. As such, it is best to keep the stickout anywhere between a quarter of an inch to about three-eighths of an inch.
- Know When to Push or Pull
If you want to create a flat and wide weld bead with a smooth surface, then you will have to push the welding gun. Know that this technique will produce a shallow penetration. If, however, you wish to produce a deeper penetration, then you will have to pull the welding gun. This will create a narrow weld bead that is high in its center.
- Always Match Everything to the Size of the Electrode Wire
Make sure that every component of your MIG welding equipment is appropriate for the size of the wire that you are going to use. For example, if you intend to use a 0.30-inch wire, then do not use a 0.35-inch drive roll. The same is true for the contact tips and the gun cable liner.
- Listen to the MIG Welder
If you hear a steady hiss coming from your welder, it often means that you have a very high voltage setting. If the noise is raspy and loud, then it is possible that the voltage is very low. If you hear a crackling sound, check your amperage setting. It is possible that it is too high.
MIG welding is easy enough to master. You can always practice your techniques before you set out on an actual welding project.
Sources:
- How to Weld – MIG Welding – Instructables
