A solder is fusible metal melted either with a soldering iron or a torch to connect metal joints together. It is typically a tin-lead alloy, but it can also come in other metals such as silver, antimony, or aluminium, made specifically for different purposes. Aluminium wires are typically soldered for electronic purposes and, therefore, require a soldering iron when fusing the metals together.
Clean the area to be soldered with a rag and a brush to remove any grease, dirt and debris. Use alcohol and a metal brush to remove stubborn stains.
Cut off the needed length of aluminium wire with scissors or a wire cutter. Use tweezers or pliers to handle the wire to avoid attracting grease.
Apply flux with a brush on the area to be soldered. The flux will remove any oxides from the metal surfaces. There are three types of flux including organic acid or chloride, organic and resin. Resin flux is common for electronic soldering; organic acid and chloride flux attract moisture and are highly corrosive.
Clean the tip of the soldering iron by wiping the tip with a damp cloth. Lightly cover the tip with solder. This process is called "tinning" and protects the soldering iron from damage caused by oxidation while facilitating transfer of heat during the soldering process.
Fire or heat up the soldering iron or torch so that it reaches the necessary temperature to melt the aluminium wire. If using a soldering iron, make sure that it reaches a temperature of at least 400 degrees C for proper soldering.
Wrap the wire around the area to be soldered. Then carefully run the soldering iron along the wire. Make sure that the soldering iron touches both the aluminium wire and joint. Heat the solder enough so that it is melted evenly along the joint being soldered. Also, make sure that the flux bubbles but not burn. Do not apply too much solder as it may fill in other gaps and cause shorts.
Remove the solder, then the tip. Be careful not to move the soldered connection.
Let the joint cool. Do not blow on it. Clip excess lead jutting from the surface but do not prematurely test the solidity of the soldered joint as it may weaken the connection. Once cooled, the soldered joint will appear smooth and cohesive.
Strip a portion of the wire and "tin" the wire by running the soldering iron along the exposed wire and melt a small amount of solder on the tip of the wire.