PCBs or printed circuit boards are used in a large variety of electronics today. Everything from computers to cell phones to digital watches uses a PCB. A PCB is a fibreglass board printed with copper strips for electronic transmission between components such as resistors, capacitors and transistors. This is done using an etching process. The components just mentioned need to be soldered to the PCB. This can be a delicate task as many components are quite small along with the locations where they are soldered.
Scrub the areas of the PCB to be soldered gently with a scrub pad. Do not use kitchen pads as these may have soap added to them. Instead use industrial or automotive scrub pads. This will remove any surface tarnish and ensure a stronger, less resistive surface to solder.
Dampen your lint-free rag with acetone and wipe away any grit or other material lifted from the scrubbing. Allow the acetone to evaporate and spray the PCB with compressed air to remove any lodged particles.
Insert the leads of a component to be soldered through the appropriate hole in the board. This can be a capacitor, transistor, resistors or other components. It is best to start with the smallest to be soldered and then move up in size.
Bend the leads on the bottom side of the PCB to hold the component in place. If the leads are small you can secure the component in place with a little masking tape.
Turn on your soldering iron and allow it to warm up. Apply a small amount of solder to the tip of your iron. The solder on the tip transfers heat better.
Hold the tip of the soldering iron against the board, where the solder pad and one of the leads meet at the hole in the board, for one to two seconds. The board and the lead need to be heated for the solder to properly adhere to it.
Remove the soldering iron and touch the tip of the solder to the component lead and the solder pad. The solder pad is a small pad next to the lead hole in line with the copper strip. If the board and lead are hot enough the solder should flow freely as you touch it to the area.
Continue adding solder until the solder pad is completely covered. You should have used a small mound of solder. If the solder applied starts to ball up stop immediately, you have too much solder. Trim the lead at the top of the mound of solder with side cutters.
Repeat Steps 6 through 8 for the other lead. Repeat Steps 3 through 8 for any remaining components that require soldering. You can skip Step 5 if your soldering iron still has solder on the tip.
Remove any solder on the tip of your iron with a piece of metal, turn it off or unplug it and allow it to cool before putting it away.
Practice soldering on scrap PCBs until you have the technique down to prevent damaging your board.
This technique requires steady hands. If you do not have steady hands you may not want to try this or you may want to practice on scrap boards first.