Can I use a soldering iron to solder a copper coil instead of an aluminum coil?

Yes, you can use a soldering iron to solder a copper coil instead of an aluminum coil. Copper has a higher melting point than aluminum, so you may need to use a soldering iron with a higher temperature setting or a higher melting point solder. Ensure that the solder you use is compatible with copper, as some solders are specifically designed for aluminum. When soldering copper, it's also important to clean the surface thoroughly to remove any oxidation, as this can affect the solder joint's quality.