Dip Brazing and Aluminum Dip Brazing

What Is Dip Brazing?

Dip brazing is a process that allows two pieces of metal to be joined together seamlessly by pouring a filler metal between the two surfaces at the melting point of the filler metal but below the melting point of the metals being joined. This results in leak-tight and EMI shielded joints. 

In aluminum dip brazing, the filler is made of aluminum and silicon. The assembly is heated to 1,025° F to ensure uniform temperature in dissimilar thicknesses and then dipped in a saltwater brazing flux at 1,095° F, which quickly and evenly heats all of the components.


Dip Brazing Process

Dip Brazing typically adheres to the following procedure:

  1. Clean component parts
  2. Subassembly and assembly of all components
  3. Confirm dimensions and adjust as necessary
  4. Apply filler
  5. Load on brazing fixture and preheat
  6. Remove from preheating furnace and immerse in salt bath
  7. Remove from bath and drain
  8. Move to quenching area
  9. Clean flux residue, inspect joints, and age harden for eight to ten hours

To ensure success, it is important to use an alloy that is capable of withstanding high heat to avoid damage to the assembly. Aluminum is very well-suited for the brazing process and provides reliable, high quality results. Assembly design is also a crucial consideration as it can affect heat transfer ability and filler flow.


Dip Brazing Applications and Materials

Dip brazing can be used on a variety of metals including copper, brass, and bronze which are often brazed with copper phosphorus silver alloys. To prevent distortion during aluminum dip brazing, it is advised to use stainless steel, Inconel, or nickel constructions. Dip brazing is a cost-effective option for parts assembly and large brazing furnaces allow for mass production of items such as electronic devices, medical equipment, and fixtures for the military.

Aluminum can be brazed, but it must be done with an aluminum alloy filler that can withstand temperatures over 1100° F. Aluminum dip brazing is particularly excellent in applications such as chassis, enclosures, and air cooled applications.


Benefits of Dip Brazing and Aluminum Dip Brazing

Some of the advantages of dip brazing include:

  • Low tooling cost. The dip brazing process uses little to no special tooling equipment. Using common fixtures allows for inexpensive configuration changes.
  • Improved strength. Aluminum dip brazing creates sturdy, leak-proof, EMI shielded joints. 
  • Less chance of product distortion. Dip brazing heats metals uniformly allowing for less risk of distortion compared to welding. 
  • Higher quality at a lower cost. The superior results of dip brazing are achieved through a cost-effective process. 
  • Superior conductivity. Aluminum dip brazing creates joints with better conductivity compared to adhesive or mechanically attached assemblies.
  • Uniform and timely. The process produces components quickly and evenly. 

Aluminum dip brazing offers all of the benefits above, plus:

  • Conductivity. Conductive to wall transitions from thin to thick.
  • Efficiency. Secondary machining operations can be minimized or excluded entirely with proper design tolerances.
  • Vertical Braze Joints. When brazing occurs in a salt bath furnace, it is possible to achieve vertical braze joints with capillary action of braze joints.
  • Ease of Assembly. In complicated assemblies, having inaccessible joints is a looming issue, but one dip brazing operation can most easily remedy this.


Aluminum Dip Brazing Furnaces and Equipment from Ajax Electric

Ajax Electric manufactures both manual and automatic dip furnaces with temperatures ranging from 1,050° F to 1,150° F and with features including removable seal tiles and electrodes, air-cooled transformers, automatic heating, and prewired cubicles with interlocking breakers. 

Ajax Electric has been the trusted provider of quality dip brazing and heat treatment equipment for 60 years. Our company prides itself on delivering quality products and excellent customer service. Request a quote today to get started on your aluminum dip brazing solution.

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