Introduction
Compared to steel or other metals, welding aluminium is quite challenging. Nevertheless, aluminium is among the most common metals that is used for melding as it has certain properties that makes it unique. It is soft, non-magnetic, resistant to corrosion or rust and does not spark. You can find its application while making aeroplanes and boats. Of course, you won’t be making them at home for pleasure, but if you know the right process and have a proper welding setup, you may go ahead and make a boat in the backyard.
Contrary to TIG welding aluminium, MIG welding is simpler and necessitates less expensive equipment. When MIG welding aluminium, it requires more heat compared to steel.
You are likely to face several issues while welding this metal such as removing the oxide layer before welding aluminium, high conductivity of aluminium, it can easily burn through or lead to cracks. So, to make it easier for you to understand the process of welding, this post will take you through a complete guide of the basic techniques.
How To MIG Weld aluminium
MIG welding aluminium is easier than you think when you know the right method. The welding procedure aids in bonding metals like aluminium together with the application of heat at a high temperature that helps in melting and fusing aluminium. Being thinner than steel, aluminium MIG welding should be done cautiously as it could easily burn through.
Here are the steps to MIG weld aluminium:
- Step 1: Collect the aluminium pieces that you want to weld. Polish them thoroughly to remove the oxide layer using a sandpaper or brass brush. Ensure to perform this step with care to prevent creating debris that might obstruct a neat weld line.
- Step 2: Secure the two aluminium pieces by connecting them and there must be no gaps before welding. You would want to achieve a clean line that fuses firmly.
- Step 3: Place the ceramic tile on each side of the aluminium to get a good grip around the metal so that you may tighten the grip vice.
- Step 4: Place your brazing rod firmly inside of your needle nose pliers. Begin heating the aluminium, but make sure to remove the flame intermittently.
- Step 5: When your brazing rod has reached a temperature of 730-degree Fahrenheit, on touching this rod onto the aluminium you will start to see a puddle of the metal emerging. So, when the aluminium becomes hot enough, it will be easier for you to mould it into the desired shape.
- Step 6: Finally, when you have moulded the aluminium into your preferred shape, avoid touching it as it would still be too hot to touch. Even though you will be wearing your gloves, it is better to let it cool off completely.
MIG Welding Aluminium
When welding, you must bear in mind that it is thinner compared to steel as already mentioned above. Therefore, you are likely to burn a hole through it especially if you are a beginner. So, you must be ready for this situation and there’s nothing to be worried about. Preferably, it is better to keep in handy some extra pieces for practice to make it an easier process. Also, choose an aluminium piece that is not thinner than eighteen gauge.
Travel speed is a common term widely used in the welding procedures. This refers to the speed at which one moves an arc over the welding metal. This also plays a huge role in welding. When welding steel, you will be able to move this arc slowly as this metal is thick. So, there won’t be much burn through the metals.
Since aluminium is thinner than steel, you are likely to burn a hole through this metal. This can happen to anyone who is a beginner. So, when you are welding aluminium, you must move the arc faster as it would give less chance to the heat to burn a hole through it.
Weld puddle is another term that you will come across when welding a metal. The small portion of metal where the arc is located melts into the liquid as a result of the heat. Your present weld puddle will soon harden as it begins to cool as you move on from it, producing the weld. The welding puddle is a red-hot, small, region of the melted metal that is immediately identifiable when it is made of steel.
The puddle will look different and like wet foil if it were made of aluminium. When working with aluminium, it requires a little sharp vision and focus to pay attention to the weld puddle.
A certain wire is needed for steel or aluminium during a MIG welding procedure. Because aluminium is a softer metal in general, the wire you use for it will also be softer. The softer aluminium wire may become rattled up if you attempt to pass this wire through a hose in the same manner as one would while welding steel.
It is simple to hunch up, which can be frustrating. However, a spool gun is a workaround. It will be considerably simpler to feed this wire directly into the arc using a dedicated spool gun. Although the spool can only carry so much wire, aluminium MIG welding will make things easier.
Safe Welding Practices
You must always set up your equipment correctly. Welding is a skill that calls for careful handling of potentially dangerous machinery. Always cross-check these things before starting:
- Check the cables: Verify that all the cables being utilised with your equipment are in excellent functioning order before starting your arc. It is necessary to dispose of and replace the worn-out cables or wires that have been cut. Keep in mind that you are working with the gas that has been heated, so one needs to eliminate any chance of sparks needs to be eradicated.
- Select the electrode polarity: Reverse polarity is necessary for MIG welding in order to complete the task. indicating that you require a positive DC electrode. You may do this with ease, and your setting would be right next to the welding equipment.
- Set the gas flow: Set the flow rate and turn on the shielding gas. You will require a flow rate that is on a higher end. This will help to deliver a higher heat rate. It is because you are welding aluminium. MIG settings are typically between 20 and 25 cubic feet per hour. Setting the proper gas flow for aluminium will get you off to the appropriate start, at about the 25-mark.
- Check the tension: To have the right tension set, it’s crucial to consider both the driving rolls and the wire spool hub. Poor wire feeding performance can result from using too much or too little. The spool needs to be able to feel the wire through efficiently as you progress through your project and weld your project component. As the machine feeds the wire through to the arc, it gradually works down and burns away the wire.
- Inspect consumables: Always Clean the contact tubes of splatter. It’s also crucial to change contact lenses’ liners and tips as necessary. Replace the wire as well if it appears to be corroded.
MIG welders will also be accountable for ensuring that their welding environment is safe and productive. This implies that they will have to decide on their wire and gas choices. They will also decide whether to push or pull when performing the task, whether to use volts or amperages, and how far the wire needs to protrude from the arc. Additionally, there are several angles and locations that must be understood in order for the welding to be successful.
Needed Protection
To prevent injuries, welders must wear protective goggles, gloves, helmets, and masks. Workers should also receive thorough training on operating equipment and potential hazards. To make sure that it is safe to use the equipment, it must be regularly inspected and maintained.
For visibility and to protect the eyes and skin from x-rays, it is advised to start with a darker lens and move up to a lighter one gradually. To help prevent burns, the gloves used should be flame resistant.
Particularly when flammable materials are present, welding poses a fire risk. The welding area needs to be close to fire extinguishers and a fire alarm. The gauge on fire extinguishers should also be checked to make sure it is full. Standard processes should be in place, providing those who find themselves in perilous situations with immediate direction. Health should be taken into account, and that includes keeping a first aid kit close by with all the supplies needed to treat any injuries right away.
Only safe locations that are clear of clutter and fire hazards should be used for welding. Flammable materials must be cleared away from construction sites. It is best to weld in a dry area.
Gas cylinders need to be handled properly. Regulators shouldn’t be switched between the cylinders, and they should be kept upright.
Equipment needs to be adequately insulated to protect welders from electrical shock. Wearing the correct gloves will prevent electrodes from coming into touch with moist skin or clothing when welding.
Keep the body of the welder sufficiently electrically insulated from the welding metal. Before welding begins, electrodes should also be inspected.
Why Is It Difficult?
Due to aluminium’s high affinity for oxygen, oxygen from the air and aluminium atoms mix to produce an oxide layer on the surface of aluminium. The first difficulty you’ll encounter when welding aluminium is that the oxide has a greater melting point than the underlying pure aluminium.
The surface oxide of aluminium has a melting point of 3700°F (2037°C), while pure aluminium has a melting point of 1200°F (650°C). In a nutshell, this means that prior to trying to MIG weld aluminium, the oxide layer must be removed.
The high conductivity of metal is the next problem you’ll encounter. This metal transfers heat from the welded junction quickly. Therefore, compared to mild steel, this alloy requires greater heat to be applied during welding.
But because pure aluminium has a low melting point and needs to be heated up quickly due to its high conductivity, there is a limited range of temperatures where it may be worked. This indicates that it is simple to burn through or to not provide enough heat to start the puddle.
In addition, as the weld cools, the volume of the aluminium welds will decrease by around 6%. Due to significant joint deformation from the ensuing strains, the shrinkage may cause cracks.
Aluminium is highly prone to pollution. As a result, it has to be carefully cleaned before being welded in a generally clean setting. Beware of cross-contamination brought on by sparks and mild steel dust that are airborne metal dust particles.
How To get Settings Right For Aluminium
The voltage required for the spray transfer was already established, but you will find several additional variables that must be adjusted precisely in order to MIG weld metals like aluminium.
In order to assist you avoid typical problems, here are the ways to set up MIG welder settings.
1. Attaching Push-pull Gun or a Spool
You will want the spool gun if you intend to MIG weld metal with your wire feed welder. Aluminium wire cannot simply be inserted into your MIG machine.
As a result of MIG aluminium wire’s lower strength than steel and propensity to attract birds to your cable liner, Because the wire isn’t as firm as mild steel wire, you must use a spool gun to make up for it.
Spool guns are useful for do-it-yourself welders, but they usually only accommodate a little 1 lb. roll inside. The advantage of using the spool gun is that the aluminium wire may avoid passing through the MIG pipe, where it will probably kink.
2. Wire Feed Settings
The choice of aluminium welding filler wire depends on the base aluminium alloy and the environmental factors that the completed component will encounter. As a result, it’s crucial to coordinate the filler wire with these two factors.
When compared to welding steel, MIG welding aluminium requires much faster wire feed rates. The MIG setting chart is often provided by welding equipment manufacturers. If this chart on the machine’s interior compartment is missing, see the user handbook.
However, a decent rule is to raise the speed of the wire feed speed used for steel by around 30–100% if your MIG welder lacks a settings chart.
3. Polarity
Setting your machine to DCEP is required for MIG welding metal (Direct Current Electrode Positive).
The electrons are leaving the machine through the ground wire and returning through the gun when the polarity is switched to reverse polarity. Your welds won’t come out if you don’t get this setup correctly.
4. Amperage Output
When MIG welding, the speed of the wire feed affects the output in amps. The deeper the penetration and the greater the amperage required to weld the metal, the faster the pace.
The welder brand determines the precise output of amperage for a specific wire feed speed. As a result, while employing a wire feeding speed of 400 IPM, 1 machine may generate 200A while another would produce 180A.
The output amperage is also influenced by the wire diameter. The amperage output decreases as wire thickness increases. Therefore, a thicker wire needs to be fed at a faster rate than a thin wire in order to produce the same amount of amperage.
While you weld, certain welding equipment indicates the precise amperage. In this manner, the amount of amperage supplied with the predetermined wire feed speed will be visually confirmed.
5. Gas Flow Rate
The majority of the time, 100% Argon shielding gas is used for welding. Hobbyist welders won’t profit from using any other gas combination, but you should be aware that helium may be added to gas mixtures to assist you achieve deeper penetration on exceptionally thick aluminium parts.
The most often used shielding gas is pure argon because it provides excellent arc initiation and stability. Helium is added to improve with penetration, but arc stability suffers as a result. It also makes the weld bead wider. Thus, pure argon shielding gas is the best option for the majority of people.
Conclusion
Because it is more straightforward to use MIG welding than TIG welding while welding aluminium, which is a challenging metal to weld. Nevertheless, if you’ve never done this before, you could believe the complete procedure to be excessively difficult.
But when MIG welding aluminium, there are much less factors to take into account. Therefore, MIG welding can be a fantastic option for a novice to get started welding this common material.
Aluminium MIG welding is not so difficult as some people think. You may work with this popular metal using MIG welding and the knowledge in this article.
Aluminium precleaning, fine-tuning your MIG welder settings, and perfecting your welding skill are the main areas to concentrate on. With a little practice, you’ll become proficient. Before you weld something valuable, don’t forget to test your welds on any scrap piece.
