Most common welding mistakes.

It is a process that is beginner friendly, and newcomers can have success with it very early on. Although the welding part seems straightforward, there is actually a lot going on inside of the machine.

These tips will cover the MIG mistakes we often see here at Gun Welding, and the best ways to fix and prevent them in the future. We have all made these errors in the past, but we persevered and learned how to correct them.

Number 1 - Incorrect Contact Tip to Workpiece Distance

Often new welders will hold the MIG contact tip either too close or too far away from their welding piece. Just like all welding processes, proper distance between your electrode and your work piece can make or break a weld.

By keeping your contact tip typically the thickness of material you are welding away from the job you will ensure that the shielding gas can create a proper atmosphere to protect your weld puddle.

SOURCE: https://www.millerwelds.com/resources/article-library/how-to-choose-mig-welding-consumables>

Number 2 - Incorrect Liner Length

Cutting the torch liner to the wrong length is a common issue in MIG welding. In most cases, it’s a matter of the liner being cut too short.

When the liner is the wrong length, it causes a poor wire feed, an erratic arc or wire chatter. For conventional liners, take out the tip holder, feed liner in the gun, keep torch straight, install liner nut, snip the excess off the front of the torch, then remove liner nut, install tip holder and reinstall the liner nut.

SOURCE : https://dynaweld.com.au/how-to-change-mig-welder-liner/>

Number 3 – A Bad Earth

Not getting the expected life of the contact tip and other front end consumables can also result if a good ground isn’t in place when MIG welding.

Without a good ground, the arc can become erratic and ultimately cause more heat build up in the front of the gun. Any problem that creates more heat will also create more resistance and more wear on your parts — damaging the contact tip and other front end consumables and impacting weld quality.

To prevent these issues, place the ground cable as close to the workpiece as possible. Grind off any paint to bare metal, ensuring your earth clamp is close. Magnetic ones are available to order though Gun Welding.

Number 4 - Selecting the Wrong Torch

A key step to prevent a MIG Torch from overheating is to choose the right Torch for the application. However, all Top Gun Welders come with the correct torch for the machine capabilities so you have nothing to worry about there

If the job requires you to weld at 300 amps all day and you choose a 200-amp torch with a 40 percent duty cycle, this torch will not be up to the task. Exceeding the torch’s duty cycle leads to overheating — and doing this frequently will shorten the life of the gun.

A change in gas can also help reduce the heat produced when welding. If you’re using an argon based shielding gas, the higher the percentage of argon, the less cooling the shielding gas provides

Number 5 – Incorrect Maintenance

It important to properly maintain the MIG Welder, Torch and the consumables, including the contact tip, nozzle and liner.

Whenever you check and change the consumables, check that the gas holes in the nozzle are clean and that the tip holder that holds the contact tip isn’t filled with spatter. Blow out your liner with compressed air. A worn contact tip or nozzle can cause overheating in the torch and handle.

Also check often that all connections are tight and as possible. Keeping the torch and welding cable as straight as possible during welding and laying them flat to cool makes for an effective and efficient MIG gun.

SOURCE: - https://weldingpros.net/mig-welder-maintenance/>

Number 6 - Incorrect Wire Speed & Voltage Settings

These are the two main settings that must work in harmony with each other. Beginners struggle with dialling these in perfectly, but it isn’t too hard. The voltage is the amount of electrical power that is running to your welding arc. Depending on wire diameter and wire type (flux, sold wire etc), voltages generally range from 16-30 volts.

The wire speed is measured in inches per minute or AMPS. The higher the wire speed, the more wire material is flowing out of the nozzle. Higher wire speeds produce larger beads. Lower speeds are great for thin material and smaller welds. 

The only reason these two settings must work together is because they are heavily related. If you have a high wire speed and low voltage, there won’t be enough power to melt the amount of wire your putting into the weld.

If you have a low wire speed and high voltage, your weld may get too hot and cause undercut or other weld defects. 

A Synergic MIG will automatically set up your wire speed and volts. Our Top Gun 210L is a fully synergic machine where you only select the material thickness and the type and the machine does the rest. – Check it out by clicking here

Number 7 - Gas Flow Problems

Beginner welder can struggle to find the correct gas flow for their jobs. For MIG, common flows rates are between 12-15 LPM (Litres Per Minute)

If you go outside of these parameters, your weld may not be as strong. Make sure that you know your parameters so you can avoid a bad weld.

For most hardwire MIG, we tend to have our gas set at 15 LPM. We find that this shields very well for most applications. If you bump up to 20 LPM or more, you will be going through a lot of gas, which is pretty expensive. 

Porosity is a weld defect that is very undesirable. With MIG, porosity is usually caused by low gas flows. If you find porosity (small holes) in your weld, the best thing to do is to turn up your gas a little. If this does not work, it could be an issue of contact distance (listed above), the angle of your torch or having bad consumables.