Can a Soldering Iron Melt Aluminum?

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Can a soldering iron melt aluminum? Well, aluminum is a metal with an incredible heat sink; this means that you will need a heat source that is high enough to get the aluminum to the required temperature. Soldering aluminum is relatively challenging compared to soldering copper. 

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It is not enough to heat up and then melt the solder even when using the right flux combined with a solder, soldering aluminum will be difficult for most individuals. To achieve this, the aluminum has to be hot enough in order for it to accept the solder alloy. 

You will require approximately 300 degrees Celsius or more for a soldering iron to melt aluminum. You will have to measure the temperature of your aluminum and not the heat source.

This can be challenging for most individuals, particularly the newbies. In this article, we shall take you through on how to solder an aluminum metal.

Soldering An Aluminum Metal

There is no doubt that aluminum is relatively challenging to join without the use of specialized welding equipment. You will be forced to track down brazing alloy or specialized solder designed to use aluminum and join two aluminum alloys for your project.

Once one of these solders is obtained, the primary challenge begins. You will have to work at an incredible speed to join your aluminum alloy once you get rid of the aluminum’s oxidized layer.

When it comes to soldering an aluminum alloy, you will need to factor the following:

Identify your alloy

If possible, it is recommended that you identify your alloy since pure aluminum can be soldered; however, it is never an easy material to work with. Most of the aluminum objects are aluminum alloys, and most of the same can be soldered in the same way. Some can be challenging, and you might force to take to a professional welder.

When joining aluminum to a different metal, in most cases, the properties of aluminum are the limiting factor. Therefore, identifying the composition of the other alloy will not be necessary. However, joining aluminum to steel is often very difficult and will require specialized welding methods.

Low-temperature solder

Usually, aluminum melts at 660 degrees Celsius, making it almost impossible to solder with a general-purpose solder. It is due to this reason that you will require using a specialized solder that features a low melting point. You should always avoid working with solders that contain lead. Always consider using an alloy designed from a combination of aluminum, zinc, and or silicon. 

Use the right flux

Just like a solder, you should look for a flux that is designed for aluminum. The best option is purchasing the flux from the same source of your solder since they often work together.

The flux and the solder should have the same melting point. If the solder you had purchased had a melting point that is above 450 degrees Celsius, you should consider buying a brazing flux. 

Heat source

Soldering iron can be used in soldering aluminum wire; however, a torch is often considered the best option. When using a torch, you should consider one with low-temperature; go for one with a flam tip that reaches 315 to 425 degrees Celsius. However, when using a soldering iron, you should consider one with 150 watts.

How To Solder An Aluminum Alloy

When soldering an aluminum alloy, you will need to follow these vital steps:


Pre-soldering each part is optional; however, it is ideal for protecting the aluminum from tinning. You can, however, ignore this step while repairing a crack or a hole in an aluminum object.

Clean your aluminum

Before you start working on your aluminum, you should consider cleaning it using a stainless steel brush. This is vital since aluminum alloy tend to oxidize pretty fast when it comes into contact with air.

The thin layer that has been oxidized should be joined. You should be ready to clean, flux as well as solder your aluminum in a rapid sequence. This will protect it against oxidation. 

Clamping the base of the metal

When connecting two pieces, you should consider clamping the two in a position that will best suit you. Ensure that you leave a slight gap between the two metals; this will allow your solder to flow along. The space should be 1 mm (1/25 inch) or less.

Applying the flux

Once you are done cleaning your aluminum alloy, you will go ahead and apply it to the area to be joined. By doing so, you will protect it against oxidation.

Heat a metal

With your soldering iron, heat the metal adjacent to the joint; you should consider starting from your workpiece’s lower end. Avoid using direct flame since it will lead the flux and solder to overheat. When using your soldering iron, allow it to heat for up to 10 minutes before using it.

Apply your solder

Usually, most fluxes tend to bubble and change to light brown once they reach the required temperature. Once this is achieved, you should drag a rod or wire of your soldering material over the joint. You should then continue heating the area indirectly; you should do it from the opposite side of your metal or the nearby surface.

Ensure that it is drawn along the gap; do it at a slow and constant movement allowing you to create a bead that is even. By doing so, you will be able to create a strong and attractive join.

Get rid of excess oxide and flux

When using water-based flux, you can rinse the flux using water once you are done soldering your piece. However, when using a resin-based flux, you should use acetone instead.

Once the flux is removed, you can have put the finished product in a pickling solution. This helps in getting rid of excess oxides that might have resulted due to high heat.

Final Thoughts

Soldering an aluminum alloy can be very challenging; however, by adhering to the tips offered in this article, the whole process will become relatively easy. As we conclude, we hope that this article has been of great benefit when it comes to soldering an aluminum alloy. 

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