Soldering is hugely important to us as a business, as almost every product and service that we provide to our customers involves soldering in some way. From PCB Assembly to BGA placement, cable assembly to SMT assembly, we’d be pretty stuck if nobody in our team knew how to solder. Luckily they do, and they do a fantastic job at it too.
Soldering is the process by which two or more items (usually metal although not always) are joined together by melting and putting a filler metal in the joint. If you think that sounds a bit like welding, you wouldn’t be wrong, as both processes are very similar. But unlike welding, soldering doesn’t involve melting the work pieces, which is why soldering is more appropriate for smaller, more intricate work. Like building circuit boards!
Soldering helps us to connect electrical wiring to electronic components, which is crucial to ensure the functionality of our Printed Circuit Boards. No pressure then team!
There are plenty of up and coming DIY electronics enthusiasts out there who might not be at the stage where they need to outsource to the likes of us to complete larger jobs, but have enough tools to complete very basic projects.
This article intends to summarise the basics in order for you to begin learning the art of soldering. The information below is for novices so if you are more experienced please get in touch with your own tips on our social channels and we will share with our readers.
First things first, read and take the necessary safety precautions before attempting. http://safety.eng.cam.ac.uk/procedures/Soldering/soldering-safety is a good place to start.
Tools and equipment
Regardless of the type of soldering work that you’re doing, you’re going to need a soldering iron and some solder to get started. A soldering iron between 25W and 30W is recommended for minor electronics work. The solder that you use should be ‘rosin core’, which can be found very easily.
Preparing the tools properly is one of the most important steps of soldering, as failing to do so can result in the tools not working properly and your time will be wasted. Grease, oxidation and all other forms of contamination need to be wiped from the tools, otherwise you’ll be dealing with globules of molten solder, which can cause binding and appearance issues. Many beginners will make the mistake of overheating the components, as they think it will help the solder to stick. This actually has the opposite effect, and can even result in irreversible damage that requires the solder to replace the components they’re using completely.
It’s vital that the components you’re working with are tinned before you begin. Tinning is the process of coating or filling wires with solder, so they can be melted together. This is a delicate procedure that requires a steady hand to be completed properly, and failing to do so will result in a weak joint.
Applying the heat and solder
We’re now ready to heat the components to be soldered. It’s important to keep in mind that the purpose of the soldering iron is to provide heat, not to shape the joint. Solder will naturally flow, so there is no need to shape it yourself. Once you’ve heated up the components, the solder can be applied. It only takes one or two seconds to heat the components up sufficiently, at which point you should start to see the solder flowing freely and creating a joint. Do not move the newly formed joint for a few seconds until the solder has cooled and has become solid. Moving the joint at this point will result in the formation of a ‘cold joint’ (a weak joint), which will result in a poor electrical connection and could prevent your circuit from working correctly.
We’re not finished yet! Your circuit might be working beautifully, but you’ve probably made a bit of a mess too. Cleaning up keeps your equipment in good condition and ensures that you get repeat usage out of it. After every joint that you’ve soldered, you need to clean the tip of your soldering iron. We use specialist equipment for this, but for a novice a damp sponge should suffice. If there is excess solder on the circuit board (there is usually a bit) then you’ll need to use a solder wick to get rid of it. This is a skill in itself, as you need to apply the soldering iron to the top of the wick to melt the excess solder and draw it into the wick, which you then need to gently pull through the joint and the iron. Tricky business but crucial if you want an effective joint.
A few more points
Hopefully you’ve managed to create your first joint for your circuit board! But there are a few more points that we wanted to address to ensure that everything goes smoothly. Firstly, you should always work in a well ventilated area. Avoid breathing in the fumes, as prolonged exposure to solder can cause health problems. While some “experts” disagree, we advise that you always protect your eyes. Safety glasses are a minor discomfort and an inexpensive investment if they help keep your vision.
If you’d like to find out more about soldering, or you’re interested in any of the services that we outlined above, please contact us today.