Braze aluminum


Brazing aluminum is more demanding and expensive than brazing other metals. There are also differences in the solders used and the burners. Below we describe the brazing of aluminum for you.

The properties of aluminum must be taken into account

The brazing of aluminum differs significantly by certain properties of aluminum:

  • low melting point
  • no tempering color when heating
  • high thermal conductivity
  • Oxidation layer with high thermal resistance
  • rapid new formation of a new oxide layer

The melting temperature of aluminum

Aluminum is exceptional over most other metals. Depending on the aluminum alloy, the melting point is between 580 and 680 degrees Celsius, in part and depending on the alloy, it can also reach up to 500 degrees Celsius.

The occasion color

While the brazing of other metals mainly uses silver solders, those for aluminum brazing mainly consist of silicon. An important aspect of brazing aluminum is the fact that the light metal does not show tempering color.

With other metals, the temperature range and thus the correct temperature range for brazing can be easily determined based on the changing tempering color. This is so far decide that the melting point begins depending on the alloy from 500 degrees, the brazing itself but only from 450 degrees Celsius is possible.

Removing the oxide layer

Therefore, the optimum temperature for brazing can only be determined from the flux and the solder, which melts in the correct temperature range. The flux must not be forgotten and must be explicitly suitable for aluminum. Because aluminum has an oxide layer on the surface.

However, the melting temperature of this oxidation layer is between 1,500 and well over 2,000 degrees Celsius, ie significantly above the melting temperatures of aluminum. If the oxide layer can not be removed, aluminum can not be joined.

It does not do any good to remove the oxidation layer by sole pickling from the aluminum or grinding. Because a new oxidation layer forms within a few minutes.

Effects of high thermal conductivity

Another fundamental property, which is often ignored when brazing aluminum, is the thermal conductivity of aluminum, which is up to 1.5 times higher than that of steels. Therefore, the temperature is quickly dissipated, especially for large workpieces. Also, two differently sized aluminum workpieces to be joined must be heated to different intensities.

Pay attention to a well-sized burner

The larger workpiece must be preheated much more intense. The mistake, which is generally made frequently, is the use of an undersized, so too small burner. The right temperature for brazing is very difficult to achieve with a torch that is too small, as it will dissipate so quickly.

High quality brazing of aluminum means to go into the material

If you consider these features when brazing aluminum, the texture becomes high quality. Of course, experience and a sense of brazing aluminum are also needed.

Tips & Tricks

Of course, we also show you in the house journal how to solder aluminum or solder it conventionally.
Braze aluminum

FAQ - 💬

❓ Is brazed aluminum as strong as welded?

👉 A properly made brazed joint (like a welded joint) will in many cases be as strong or stronger than the metals being joined. Second, the joint is made at relatively low temperatures, ranging from about 1150°F to 1600°F (620°C to 870°C).

❓ Is it better to braze or weld aluminum?

👉 Quick repair: Aluminum brazing is a much faster metal-joining technique than TIG welding and other forms of welding. Since it has equivalent strength to these other metalworking skills, this makes aluminum brazing a good option for metalworking jobs that must be performed fast or as part of an assembly line.

❓ Can you braze aluminum with a propane torch?

👉 Yes, you can weld aluminum with a propane torch and aluminum brazing rods as long as it is for non-structural metals that are not weighted or stressed or critical parts. Propane torches are usually do not reach high enough temperatures to be capable of performing effective aluminum welds.

❓ Will brazing rod work on aluminum?

👉 With a low working temperature of 720 to 750 degrees Fahrenheit, these rods can also be used to build-up aluminum joints without distortion, discoloration, or loss of strength. Tensile strength of 33,000 psi.

❓ Does brazing aluminum require flux?

👉 Aluminum braze flux is required in all aluminum brazing operations. Aluminum brazing fluxes consist of various combinations of fluorides and chlorides and are supplied as a dry powder. For torch and furnace brazing, the flux is mixed with water to make paste.

❓ Is brazing permanent?

👉 Brazing is a process in which metals are joined by melting a filler metal into the joint to create strong permanent bonds.

❓ What type of brazing rod is used for aluminum?

👉 Super Alloy 5 aluminum brazing rods are the rod of choice when brazing thin aluminum parts.

❓ Do you need flux to braze aluminum?

👉 Aluminum braze flux is required in all aluminum brazing operations. Aluminum brazing fluxes consist of various combinations of fluorides and chlorides and are supplied as a dry powder. For torch and furnace brazing, the flux is mixed with water to make paste.

❓ What kind of brazing rod do I need for aluminum?

👉 Super Alloy 5 aluminum brazing rods are the rod of choice when brazing thin aluminum parts.

❓ How do you prep aluminum for brazing?

👉 To summarize, take the following steps before welding aluminum:

  1. Remove oil, grease, and water vapor using a solvent or mild alkaline.
  2. Remove surface oxides with a wire brush or strong alkaline or acid.
  3. Assemble the joint. ...
  4. Keep the joint dry.
  5. Weld within a few days.

❓ Can you braze aluminum with a heat gun?

👉 0:262:16How to "Weld" Aluminum Without a Welder

👉 Aluminum brazing is a popular metal-joining technique that has several advantages over other forms of welding. Brazing is a form of torchwork that involves joining two pieces of metal with a nonferrous flux using gas that is heated to roughly eight hundred degrees Fahrenheit. Why choose aluminum brazing over welding?

👉 Brazing with aluminum can refer to joining 2 metals together with aluminum flux, but it could also refer to the process of joining 2 pieces of aluminum together with some other kind of flux. Either way, the overall process is identical. To braze 2 metals together, get a brazing flux, some brazing rods, and an oxy-acetylene torch.

👉 For brazing aluminum, a commercial gas mixture containing oxygen and propane is typically used. This gas mixture provides a very hot flame that is capable of melting aluminum, which then joins the two pieces of metal together. What Gas Is Used For Brazing Aluminum? The most common gas used for brazing aluminum is a mixture of oxygen and propane.

👉 Step 1: Thoroughly clean the workpieces and the brazing area to remove oil, grease, and aluminum oxide. Use an emery cloth to remove oxide coating on the brazing area. Wipe the brazing area clean. A clean brazing surface is very important for a good brazing joint. Step 2: Clamp the aluminum workpiece securely using a clamp or on a vice.


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