Compared to mild-steel, MIG welding aluminum can be a hard nut to crack. If you haven’t yet got a good hold of welding mild-steel, you probably need to get a good grip on MIG-welding first.
But if you are really into MIG welding aluminum, we got you covered. In this article, we will be guiding you, step by step, on how to weld aluminum with MIG welder.
Well, let’s start it then!
Some Key Factors On Aluminum Welding
When you are using aluminum in its original and pure form, you can find it as a soft metal. This can be used for many purposes. But to serve the best, it does need some helping hands of extra alloys.
Being in connection to steel, the properties of aluminum can vary greatly. It can also mean that the material is prone to distortion, or it can imbalance the heat sensitivity of it.
However, if you are into MIG welding aluminum materials in its truest form, it shouldn’t be that challenging. But that’s only if only you are using the right tools and machine. Together with the equipment, following the proper procedure can make your job a lot easier.
So before you move on, keep these crucial factors in mind.
Thickness Of The Material
To MIG weld, the thickness of the aluminum material should be about 14 gauge or more. The welder you are using can vary with output capacity. And this capacity indicates the thickness that you can weld with it.
If the material you are trying to weld is thinner than 14 gauge, you may have to think otherwise. Get a specialized MIG welding equipment that can support in this case.
Before you even start, make sure to clean the aluminum material. The cleaning should be thorough and proper so that no lubricant can get stuck to the material.
Consider degreasing it using a wire brush made from stainless material. You can choose between a wire brush or a cup wire type. Either will work. If you are using a power wire brush, you need to keep the RMP and the pressure as low as possible.
This will reduce the covering from the surface of the material. Otherwise, it will hold the oxides and other impurities beneath the surface.
To avoid this contamination, make sure to clean it with a wire brush that is always used on aluminum.
Only after the degreasing, you can remove the oxide.
Select The Suitable Gas
Aluminum needs pure argon shielding gas. This is because the material is a non-ferrous type. Set the rate to 20 to 30 CFT/Hr for the best possible result.
Selecting The Procedure
Now, you need to select the method you will use for the welding. For MIG welding aluminum, the best method should be the spray transfer one. In this method, the molten droplets can be transferred from the electrode end to the pool.
The measurement of the diameter of the droplets that cross the arc is pretty smaller than the electrode. You don’t expect that much of a short-circuiting in this method. The efficiency level of it is considerably higher than any other mode.
But, you need to be careful as this method deals with a high amount of temperature. That’s why you should use it on materials that are thinner than 14 gauge.
Wire And Gun Feeding Type
Before you go for the MIG welding, it is vital to choose the right gun and wire feeding system. In most cases, you have to feed the aluminum wire simply with the help of a spool gun. Alternatively, you can use a push-pull system, too.
Spool guns locate a small wire-pool on the style gun. This improves the feeding that comes with the soft wires. As the wire can be fed only a few inches in it, you don’t need to worry about any bird-nesting inside.
Techniques Of Welding
The weldability of aluminum depends on multiple factors. How skilled the operator is, the joint types, fit-up, and the position – these are crucial factors in determining successful MIG welding. In addition to these, the welding power supply also plays a vital role in this.
Setting The Push Travel Angle
Set the push travel angle to a 10 to 15-degree angle. The tip, as well as the nozzle, should be placed as pointed towards the direction of the travel. If you are doing it otherwise, it will call for the production of dirty welds as the gas coverage will be lower.
Keeping The Tip-To-Work Distance
You have to keep a tip-to-work distance properly. Again, make sure that the contact tip has gone around 0.125 inches inside the nozzle.
Hold the tip at the recommended distance so that the wire doesn’t burn back to the contact tip. This is because the reflective heat and the weld puddle get pretty heated up when you are MIG welding.
You will need to increase the level of the torch while the base material gets heated up during the welding process.
Solving Common Problems
While MIG welding aluminum, chances are there that you may face a few common issues that most welders face. Here’re some tips to get rid of these problems.
Burn-through For Overheated Base Material
For this, you need to increase the speed of travel and shorten the welds. Consider moving around the part to spread the heat out. Also, try to use thick materials and change the design of the joints.
Welds Getting Dirty
In this case, you should consider replacing the drag technique with a push angle one. Try to increase the voltage, if possible. Using accurate base metal cleaning methods can work for you.
Machine Setting Error
You need to check the inside of the machine for the optimum starting setting. This way, you can fine-tune the application.
Wires Burning Back
This is an annoying problem for most welders. However, getting rid of it is easier than you thought. Just make sure you are maintaining a proper tip-to-work distance. Again, the wire diameter should match the drive rolls, size of the tip, and the gun liner, as well.
This is a very common problem when you try MIG welding on aluminum. To solve it, you should check the drive roll tension and adjust it if there is a need for it. Again, make sure the rolls are matching with the wire diameter.
If the contact tip seems to be gone out of hand, consider replacing it. And finally, adjust the pressure on the spool gun hub.
If you thought that MIG welding aluminum is a hard job, we guess this piece should make you think otherwise. Follow the tips and techniques we have discussed here to decode how to weld aluminum with MIG welder. With that, try to keep our troubleshooting guide handy.
Good luck with your welding!
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