MIG welding can be one of the simplest processes to master. It takes practice to become a good welder. To get started you should take a MiG welding for beginners course.
To get started with MIG welding you need to follow a few important safety tips. This includes using an auto-darkening welding helmet and taking some time to find a comfortable position.
How To Set Up The Welder
Make sure that your MIG welder is properly set up before you begin. You can adjust the voltage, wire feed speed and other settings according to the thickness of the metal you will be welding.
If necessary, you can also change the polarity of the electrode. Standard MIG welding requires DC electrode positive polarity, while flux-cored welding requires DC electrode negative. Attach the ground clamp. The best ground is copper, which conducts electricity well and won’t crack.
Once you’ve got the settings just right, it’s finally time to start welding. Before you start, you should experiment with the way you move the gun. Different techniques can have a significant impact on your welds. For example, dragging the gun too slowly can build an oversized bead, while moving it too fast can diminish penetration.
Welding is a technical skill that requires practice and precision. If you are new to the field, consider taking a class in welding at a community college or technical school.
Preparing The Material
MIG welding has become a standard process in many metalworking processes. It is suitable for mild steel and stainless steel. It is a simple and quick method that produces high quality welds, with little distortion and spatter.
Before you begin welding, ensure that the metal is free of grease and oil. Remove any paint or rust on the metal surface. The cleaner the metal the better the weld.
After cleaning the workpiece it’s time for the welding equipment to be set up. Make sure that the cables are connected with the correct polarity, and adjust the gas flow. The best mixture is 75 percent argon, 25 percent carbon dioxide. This provides good penetration, has minimal spatter and doesn’t promote burn-through on thinner materials.
You can also use 100% CO2, but it takes more practice to get better results. Once you have your settings established, it’s time to start laying welds. Start by making small welds in sheet metal to learn about the power settings.
Setting The Wire Voltage, Speed
The quality of the weld is affected by many factors. The wire feed speed, the electrode thickness, and the voltage are all important factors. Most manufacturers provide charts with different thicknesses for metals that show the amperage required for each as well as a starting point.
Voltage affects length of arc which determines height and width of weld bead. Generally, each 0.035-inch increment of material thickness requires an increase in amperage by 1 amp per volt of power.
Try them out on a scrap piece of metal to get an idea of how they affect the weld. Then, replicate the results with a real-life project. Keeping in mind the factors discussed earlier, such as the position of the workpiece and the way you move the gun, you can start to see how small changes impact the outcome. Moving too quickly, for example, can cause an oversized bead that reduces penetration. Moving too slowly can result in a weak, sloppy joint. The way you weave or oscillate the gun may also have a noticeable effect on the quality of a weld.
Oscillating Gun
While you could just point the gun at the joint and start welding you will get better results by moving your arm around slightly. This technique is called weaving and allows you to control size, shape, and cooling effects of your weld puddle. Weaving also helps you to avoid blobs and a large weld pool that reduce penetration.
For overhead welding it is a good idea to keep the gun tilted upward anywhere between 35 and 45 degrees. This prevents the melted metal from flowing to the bottom of the work piece. Keeping the gun in this position will help you avoid a lot of spatter that burns up your elbow. You can also move your gun from side-to-side or in a slight arc to control the penetration and weld pool.
The way you move your gun will determine the amount of heat that is applied to the wire, and whether it is in a spray or globular mode. Too little power will produce a small pool of weld, while too much will burn through the material.
Keeping Your Arm Still
While it seems obvious, it’s important to keep your arm as still as possible. Even the slightest motion can affect weld quality by causing slag accumulation or an excessively wide weldpool. You can also drift outside the recommended parameters which will cause a poor arc and increase spatter.
You can control this by monitoring your stickout or the distance between the tip of the electrode and the workpiece. A longer stickout can make the arc softer and create a more fluid weld pool. Too short of a stickout can cause undercut, where the base metal is melted along the edges of the weld without being completely welded to the rest of the weld.
Use the scratch start technique or the tapping technique to begin the weld. If your arc is erratic or wandering, it may be because the electrode isn’t dry. Use low hydrogen electrodes and twist the electrode tip if it sticks to the workpiece.
