When you work in the HVAC field, you need to have a wide range of skill sets because heating and cooling systems require you to know everything from plumbing to electricity. But one of the things that not many people discuss is just how important it is for a tech to know how to work with galvanized sheet metal.

Galvanized sheet metal is what is used to make the ductwork for every HVAC system, and because every installation is unique, an installer needs to know how to cut and work with the material, so they can fabricate a network of ducts that are leak-proof and capable of delivering forced air efficiently throughout the structure.

Since so much of your time on the job will involve working with galvanized sheet metal, this post will serve as an introduction to the metal, so you can have a better understanding of why it is used and how to get the best results from it.

What is Galvanized Sheet Metal?

Galvanized sheet metal is a sheet of steel that has been coated in zinc to make it resistant to corrosion. Because steel is made of iron, it will quickly rust when exposed to moisture, and over time that rust will corrode the steel to the point of failure.

By coating the steel in a layer of zinc, a barrier is formed between the sheet metal surface and external environment. This prevents corrosion and rusting and allows the metal to be used in a variety of environments, including harsh weather conditions. Galvanized sheet metal is so durable and long-lasting that it is used not only in HVAC ductwork and throughout the construction industry, but also in the automotive industry, the electronics industry, power generation and communications, food processing, and in road construction, among others.

How is Sheet Metal Galvanized?

Steel sheet metal can be galvanized using a few different techniques. These include:

• Hot-dip galvanizing: This is a popular technique that has been used for more than 100 years, and it involves submerging the sheet metal in molten zinc. Of all the techniques, hot-dip galvanizing is the most economical, reliable, and durable way to galvanize steel sheets.
• Electrogalvanizing: This type of galvanization relies on electroplating. The electroplating technique bonds the zinc layer to the surface of the sheet metal. This allows for a very thin and accurate layer of protection that also has a better surface finish.
• Sherardizing/Dry galvanization: This technique involves heating fabricated sheet metal parts in a rotating drum with metallic zinc. As the zinc dust evaporates, it will diffuse into the sheet metal. This is ideal for sheet metal parts that have already been fabricated and require zinc coating on its inner section.
• Thermal spraying: Thermal spraying involves spraying the surface of the sheet metal with a coating of zinc. As the zinc particles land on the sheet metal, they flatten and adhere to the surface. The sheet metal is then heated to complete the galvanization.

Galvanized Sheet Metal Fabrication Considerations

Working with galvanized sheet metal is an art form that can take some time for an HVAC technician to perfect. This is because the metal can be difficult to work with for those with little experience and problems can arise when bending or welding it.

For instance, when someone without the proper training bends galvanized sheet metal, it can be common for them to experience cracks in the galvanization. In fact, even experienced HVAC techs can have this happen to them from time to time. When this occurs, there are two options for you to consider – you can repair the cracked sections, or use more advanced sheet metal galvanization techniques.

Likewise, welding galvanized sheet metal can sometimes present challenges. In many cases, it can be difficult to achieve a consistent and uniform weld on galvanized sheet metal. Your only option here is to closely monitor the entire welding process to ensure compatibility. Or, you may need to fabricate the ductwork sections and galvanize them later, but quite often that isn’t possible.

Another potential problem that you might run into when fabricating galvanized sheet metal is surface distortion and warping. When this occurs, it is usually indicative of a problem in either the fabrication’s design or the sheets being used aren’t uniform in thickness. When you are using a proper design and fabricating sheet metal parts with uniform thickness and symmetrical designs, you will be able to significantly reduce or even eliminate surface distortion or warping.

Master the Art of Galvanized Sheet Metal Fabrication

It’s one thing to learn about galvanized sheet metal, but if you want to work efficiently with the material in your HVAC career, then enrolling in BTrained’s Metal Duct Design & Fabrication Workshop will help you master the art of duct fabrication. This comprehensive three-day program is specially designed to provide you with the education and hands-on experience you need to improve your skills in this vital part of your job responsibilities as a professional HVAC installer.

BTrained can help you become the best HVAC tech you can be. Since each of our training courses have a limited number of seats available, they tend to fill up quickly, so it’s recommended to claim your spot early. Enroll today and secure your spot.