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What is the Best Flux for Soldering Galvanized Steel?

What is the Best Flux for Soldering Galvanized Steel?

What is the Best Flux for Soldering Galvanized Steel?

If you are soldering any type of sheet metal, it is important to choose the right flux.  Flux plays a vital role in soldering as it enhances the bonding of the joints and improves the performance of the soldering process. 

Flux also helps to remove the oxides from the metal to allow it to bond properly with the solder.   And when you have the correct flux, the connection will be that much smoother.

It's important to note that when working with galvanized steel, you should use a flux that is compatible with the galvanized steel that you are soldering.  Some fluxes are specifically designed for use with metals like zinc and are more effective in preparing the surface for soldering. 

For soldering galvanized steel, the right flux will get the best hold on your galvanized steel surface.  A zinc chloride-based flux will get you the best flow onto the base metal.  A great liquid flux that has an active chloride formation like Johnson’s Galvanized Steel Flux is a great choice for galvanized steel. Make sure to brush the flux wherever the solder makes contact.  The solder follows the flux.



Below are 4 reasons why flux is needed in soldering galvanized steel:

1. Flux facilitates the wetting and solder flow

Flux plays a key role in solder flow and wetting. Wetting is the ability of the solder to spread and adhere to the metal surface to help ensure a solid bond. Flux, made of an activator, facilitates wetting by helping to reduce the surface tension of the solder allowing it to flow more uniformly and smoothly over the sheet metal.  Proper wetting means that the solder joint was correctly formed.

Flux helps the solder to "wet" the surface of the galvanized steel. Wetting refers to the ability of the molten solder to flow and spread across the metal surface. Without proper wetting, the solder may form beads or blobs, resulting in a weak and unreliable joint.

2. Flux removes oxides as well as prevents further oxidation:

Galvanized steel can develop a layer of zinc oxide on its surface due to exposure to air. This oxide layer can hinder the solder's ability to bond with the steel. Flux works by removing these oxides, allowing the solder to make a strong and secure connection.

During the soldering process, especially when the metal is heated, more oxides can form. Flux acts as a protective barrier, preventing the formation of new oxides, which ensures a cleaner surface for the solder to adhere to.

3. Flux helps with heat transfer:

Another function of flux is to improve the heat transfer during the soldering process. Flux acts as a thermal conductor and it helps to distribute the heat evenly across the metal surface. This helps to create a consistent soldering temperature and prevents either under or overheating. By achieving the ideal soldering temperature, it helps to create optimal solder flow.

4. Flux acts as a cleaning agent:

Flux also acts as a cleaning agent as it removes dirt, grease, and contaminants from the surface of the sheet metal.  These impurities hinder the solder from bonding correctly and lead to weak solder joints.  Flux dissolves these impurities and allows the solder to adhere correctly to the clean metal surface.  Proper preparation of the surface with flux helps ensure the contact between the solder and the sheet metal and results in more reliable and stronger connections.

Flux is an essential part of the soldering process. It helps to improve the flow and wetting of solder, prevents oxidation, acts as a cleaning agent, and improves heat transfer. By using the right type of flux and tool applying it correctly, you can ensure that your solder joints are strong and durable.

Remember to follow safety precautions when soldering, especially when using flux. Make sure to ork in a well-ventilated area and use appropriate personal protective equipment. Additionally, always refer to the manufacturer's instructions for the specific flux you are using, as different fluxes may have unique application and cleaning procedures.



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