Learning to solder aluminum metal sheet is a great skill to add to your DIY toolbox. Soldering is the process wherein two or more metal items are fused together by melting a filler metal into the joint. While soldering is generally easy, it becomes more difficult when working with certain materials. One of the most difficult materials to solder is aluminum sheet metal because the aluminum oxide film on the aluminum sheet metal is so stable that it is very difficult to remove, even using heat from the soldering iron. Consequently, it is very difficult to solder and create strong joints on two aluminum sheet metals.
This is the reason why a lot of DIY enthusiasts avoid working with aluminum sheet metal. However, here are some tricks on how to properly solder an aluminum metal sheet.
Step 1 - Clean Your Aluminum Metal Sheet
Use a clean rag to wipe your aluminum sheet metal from any dirt and apply a solvent or grease remover to remove oil or grease. This step is necessary because when you are working with aluminum, it is very difficult to solder it properly this you need to remove any obstructions from the metal sheet to facilitate the soldering process.
Step 2 - Set the Aluminum Sheet Together
Set the aluminum sheet together and ask a friend to hold both sheets firmly in place or you can use clamps to secure the aluminum sheets together. Before you proceed to the next step, make sure that you wear the necessary gear like a pair of work gloves, goggles, and a long-sleeved work shirt to protect yourself from sparks.
Step 3 - Apply the Flux on the Area to be Soldered
The next step is to apply flux to the areas where you need to solder. The flux is a chemical cleaning agent that facilitates the soldering process by means of removing the oxidation from the material you are working with. The flux extremely important when fusing a difficult aluminum sheet metal with another material.
Step 4 - Heat the Flux and the Metal with a Torch
Heat the area where you need to solder using a torch. Make sure that the solder metal or filler melts instantly. Do not apply heat directly to the solder filler to prevent the solder metal from burning up. You will know that the aluminum sheet metal has been soldered properly using the flux and solder metal if the molten filler flow onto the aluminum and seeps inside the joint but if it just rolls off, you need to try another flux and solder metal and repeat the process until you observe seepage of the metal to the aluminum joint.