Connect the end of the lead cable to the cable extender. Use your pliers to tighten the connection.
Turn on the soldering iron and allow it to heat up. Touch the end of the soldering iron to the solder and allow the solder to melt.
Drip the solder over the point of connection between the two cables. Continue to do this until the solder evenly covers the entire circumference of the point where the lead cables are joined.
Wrap the entire connection in magnetic tape. Use two to three layers to cover all exposed parts of the connection.