HOW TO: Solder

Expert guide to making professional electrical connections.

Wiring can be a time-consuming and frustrating task, especially when it comes to connecting wires and creating a professional-looking finish. Crimped terminals and quick-splicing connections certainly save time, but they often don’t seem to be as reliable as a soldered connection and certainly don’t look as professional. So, if you want to make a good job of your wiring, soldering the connections is still favoured by many people, whether it’s a case of permanently joining two wires together or fitting connectors such as bullets or spades. A good finish to your wiring is well worth the effort.

There are several safety issues concerned with soldering wires together. The heat generated by the soldering iron can burn your skin and melt or set fire to objects it comes into contact with, so use a stand to keep the heat away. Some soldering irons are sold as a complete kit with a suitable stand, but stands are also sold separately and cost from around £5. If you are using a heat gun to warm up heat shrink and wrap it around exposed connections, this can also get hot and cause burns or fires, so leave it to cool down before putting it away.

The gas emitted from the solder wire (it’s made of tin and lead) is poisonous, so work in a well-ventilated area and consider wearing a breathing mask. Similarly, if you are using a gas-filled soldering iron, waste gases shouldn’t be inhaled, so make sure there is good ventilation.

If you are planning to rewire a car or solder lots of wires together, then it’s worthwhile investing in the right equipment to save time. A good quality pair of wire strippers will halve the time taken to strip the insulation off the end of a wire when compared to a budget pair or a pair of side-cutters. A soldering iron with a variable heat setting will reduce the risk of melting solder that has already been applied. And an assortment of tips for the soldering iron will help to tackle a greater range of jobs more accurately.

The following steps outline the equipment and materials you need to solder wiring, how to solder wires together and wires to connectors, and the typical problems that can arise when soldering.