Soldering galvanized steel is a different process than soldering uncoated metals. Galvanized steel is coated with zinc to prevent corrosion. If soldering is done improperly, the steel might not be resistant to weather, rain or other outside harm. And it can rust more readily.
Below are 5 steps to get the best soldering out of your galvanized steel:
1. Clean the surface thoroughly
Take a piece of sandpaper or a steel wool brush and smooth the surface where you plan to solder. The sandpaper can help remove some of the metal oxidation that might make it harder for the solder to bond to it.
2. Remove dirt or leftover grime
Then you should wipe down the steel along the area that you just sanded. A degreaser or cloth can be used to get rid of the dirt or any grime and dust that is leftover from the sanding. It’s best to solder right after cleaning before any other dirt or oxide attaches to the galvanized steel surface.
3. Choose the right flux
Just as in soldering stainless steel, it is important to choose the right flux to get the best hold for your galvanized surface. In general, use a zinc chloride based flux to get a good flow into the base metal.
Choosing the right flux is important and for galvanized steel, a liquid flux is usually recommended. It is best to use a liquid flux with an active chloride formation such as Johnson’s Galvanized Steel Flux.
Brush the flux wherever the solder will make contact; the solder follows the flux.
4. Apply Heated Iron
Heat the iron or torch to the highest heat setting. Then hold the tip of your tool against the sheet metal lap seam. Apply the solder bar to the heated lap seam adjacent to the iron.
Continue to hold your iron against the metal until you finish applying solder to the area. As the molten solder flows into the seam, move the heated iron to the next section of the seam.
5. Clean the Flux And The Surface After Soldering
Clean the excess flux off as well as the leftover solder after you have finished soldering. Wipe the surface down with a damp cloth or flush with clean water to prevent corrosion.
If you have any questions about soldering galvanized steel or which solder is best to do so, please contact our technical support team. They would be happy to help you!