Alloych solder

Aluminum or aluminum can also be added. These include techniques such as soldering or welding. While welding is a bit more involved, DIY enthusiasts can also solder aluminum sheets with their simpler options. Below you will find everything you need to know about soldering aluminum sheet.

Special features of aluminum

Perhaps you have heard in your environment that welding and brazing aluminum is more complex or does not work depending on the alloy. In addition to an unfavorable alloy, this is mainly due to the oxide layer that forms on aluminum. In addition, it is also important to know where the difference between soldering and welding is.

Soldering the definition (soldering)

During welding, both materials are melted: the workpiece and the welding wire. Both materials are mixed together. Soldering works a little differently. The solder diffuses partially solid or gaseous into the surface of the alloy to be soldered.

The different melting temperatures

This can be compared to a sponge that absorbs water. If the material to be soldered cools down (in this case, the water freezes), both materials are firmly connected. But now the oxidation layer comes into play with aluminum. To better explain the problem of soldering aluminum sheet, first of all the melting temperatures:

  • Lot: 400 to 450 degrees Celsius
  • Aluminum sheet: 580 to 680 degrees (depending on the composition of the alloy)
  • Oxide layer: over 2,000 degrees

So put the sponge full again. The water is liquid above 0 degrees. The oxidation layer will now be a plastic wrap around the sponge. So it does not melt from the melting point of the water, so this can not penetrate into the sponge.

Remove the oxide layer from the aluminum sheet before soldering

Therefore, the oxide layer must first be removed before soldering the aluminum sheet. This works mechanically or chemically. The disadvantage of mechanical removal: the aluminum surface begins to re-oxidize immediately when it comes into contact with oxygen, ie the ambient air. It must therefore be soldered very quickly (the oxidation layer is formed within a few minutes).

Chemical removal of the oxidation layer

The disadvantage of chemical removal is that, depending on the process (alkaline, with acid, etc.), the aluminum sheet can not be further processed at will, for example, sticking to the aluminum sheet. But it works when soldering. Here you can resort to flux for aluminum, which also remove the oxide layer.

Soldering of different sized workpieces

If, for example, you want to solder an aluminum sheet with a large aluminum body, both areas of the two workpieces will not heat evenly due to the different dimensions. As the thicker aluminum, you need to heat more intensively to heat both workpieces evenly. For this they should bring larger aluminum body to about 200 degrees. As a home improvement, you can do that with the help of the oven.

Summary when soldering aluminum sheet

Degrease the aluminum. Then brush off the area to be soldered or apply the flux according to the manufacturer's instructions. Heat the aluminum sheet to at least 200 degrees Celsius. Then melt the Alulot at a temperature around 450 degrees and apply it to the aluminum sheet. Now let it cool down.

Tips & Tricks

Note the different alloys of aluminum or cast aluminum. Aluminum sheets often have high levels of silicate and magnesium.

It is not always necessary or even sensible to solder an aluminum sheet. Then you can glue this aluminum sheet too. Here we even show you how to glue aluminum to wood. During soldering and welding, artificial aging of aluminum may also be important.

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