Unlike welding, there are considerable steps or parts to the process of aluminum brazing. By paying close attention to each of the steps, which will vary slightly depending on the specific assembly or parts, the best and most durable joint can be created with consistency and accuracy.
Just like any other process, skipping particular steps in the aluminum brazing process can not only lead to a poor joint, but it may also cause leaks and incorrect fitting of parts that can cause significant damage over time depending on the use of the specific part.
One of the most important aspects of aluminum brazing, or other types of metal brazing, is to have a completely clean surface. This allows the filler and flux to flow over the surface and into the joint where the filler actually forms a bond with the base metals to create the strong, durable joint.
Grease and oil, or even the residue from your hands, can limit or prevent this flow of filler material. Likewise you should remove all visible signs of rust, oxidation, dirt or surface irregularities to allow the correct capillary action to draw the filler into the joint.
Before you start the process of aluminum brazing you have to have the two parts that you want to join completely secure and in place. They will need to remain in place, without moving, while you apply the flux, heat the filler and allow the joint to cool.
In some cases gravity will hold the parts in place, or you may use clamps or, in the case of aluminum dip hi-temp brazing, a basket or form that will allow you to lower the part into the bath.
Depending on the part and the type of aluminum brazing there are different options to use for flux. A general or all-purpose flux is typically all that is needed for small repairs but in dips and specialty types of parts different flux types are essential for the best possible movement of the filler into the area to the joined.
Generally for larger parts where a significant area is going to be subjected to aluminum brazing, dipping is the best option. This provides a uniform amount of flux to all areas to be brazed, helping to eliminate areas of inconsistency over the part.
Hi-Temp Brazing provides Aluminum Brazing Services to deliver high-integrity assemblies for critical applications in a range of industries.
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