Soldering is a fantastic skill that’s pretty easy to learn. Using a soldering iron you use the heated tip to melt soft metal and let it flow onto components to stick them together with a strong connection. Soldering can help you make your next great invention, help you fix things and can help you learn about electronics. Let’s get you started!
The basic tools for soldering are a soldering iron which come in a range of sizes, prices and have a range of features. The good news is that to get started a small an cheap one that doesn’t have an fancy features and just gets hot on the soldering end is all you need. There are some budget USB powered ones which are very affordable and are great for electronics learners.
Other tools include a stand into which you can place the soldering iron when it is hot to stop it from burning surfaces and to keep it safe, many stands have either a small sponge built in which you can make wet with a little splash of water and then use this to wipe and clean the tip and remove any solder on it you don’t need. Other stands have steel wire pads to do the same job and both work well. Obviously you’ll also need some soldering wire. Solder comes in a range of thicknesses and for beginners it’s recommended to use some solder between 0.6mm and 1mm. Solder is a mixture of different metals, some solder is lead free and some solder has lead in it. Any general solder is fine for beginners and many beginners start off with solder containing lead as it’s slightly easier to work with. Whatever solder you use you need to take care to wash your hands very well after handling it and also make sure you work in a well ventilated area and avoid breathing in any fumes. If you really get into soldering regularly it’s a good idea to invest in a fume extractor which will move the fumes away from you and filter them, however to begin with using a fan to move the fumes away towards a window or vent can work well
Many solders contain flux which is a chemical which helps clean the metal areas the solder is going to stick too and it can be useful to have some extra liquid flux which can be brushed onto potential solder points. Finally it’s a good idea to have a board or surface that you don’t mind potentially getting damaged to work on and you might find a 3rd hand tool as pictured useful to help you hold onto items.
So before we start, a quick mention of safety. Lots of people think soldering is dangerous but if we are sensible it’s a very safe hobby. The tip of the iron is extremely hot often above 380C and yes it will burn you and quite quickly give you a blistered burn if you hold the hot end. In practice though you are very unlikely to hold onto it for long! Human reflexes tend to pull our hand away very quickly if we accidentally touch it. It’s worth wearing some safety glasses as this will stop smoke and fumes irritating your eyes and also if the hot solder splashes, which is again unlikely, your eyes would be protected. If you do burn your fingers or hand, hold your hand under cold water for as long as you can manage.
A great place to start a soldering adventure is to buy a small electronics kit. Some electronic components are mounted with their wire connections passing through a hole on the circuit board, this type of construction is called “through hole” or “through hole mount” and these are the best kits for beginners. Other electronics components are much smaller and sit on top of the circuit board and are called Surface Mount Devices or “SMD” and they are more advanced to work with at first!
There are thousands of kits online and in electronics shops to chose from, pick something simple and fun and follow the instructions paying attention to where parts go.
Soldering a through hole part is simple. Make sure the part is the right one and bend the leads to fit the part in the right place on the circuit. Leave the excess leads on until the component is soldered in and you can even bend one of the leads to help hold the component in position.
Power up the soldering iron and let it heat up, you can check when it is hot enough by touching a length of solder wire to the tip and it should melt easily and form a small blob on the irons tip. Clean the tip one last time and then lets solder our component.
Place the tip of the soldering iron so that it touches and heats both the component lead and the metal pad on the circuit board at the same time and let it heat for a few seconds. Then push a small amount of solder into the end of the tip and the solder should melt and flow all around the pad and the lead. Remove the iron and wait a few more seconds for the joint to cool down. There you go you have soldered your first joint! Check the joint and make sure the solder looks quite shiny, if it looks very grey and dull that can be a sign that your joint isn’t quite right and you can reheat it to redo it. Once you are happy you need to trim the component leads back to get rid of the excess, this is actually the most dangerous bit of soldering as when you clip the lead the sharp pin like lead can fly off in any random direction! Always hold the lead so you catch the removed bit and wear eye protection.