If you are a STEM Star, you’ve certainly soldered many times by now and feel pretty confident with a soldering iron. But if you’re a parent or a friend, you’ve probably heard about it, ,maybe you’ve even seen the tools before, but it is not a skill that you have felt compelled to tackle. I’m here to assure you that anyone that can hold a pencil can solder! All you need is the ability and maturity to handle the hot iron safely and a desire to learn!
To begin, we will review the tools used in soldering, why we use them, when we use them, and how to use them safely.
What is Soldering
Soldering is the joining of two items by melting a material called solder which then bonds to each of the surfaces, creating a joint. The term soldering is used in plumbing and jewelry making as well as electronics, and though the techniques may be similar, the equipment and techniques discussed here will refer to electronics soldering only. Soldering is an essential skill for the electronics enthusiast and is one that, with a little practice, is easily mastered.
To properly learn the art of soldering, there are certain tools you need to have. Below, we will discuss each tool and its basic uses. The use of safety glasses is highly recommended. For those with longer hair it should be tied back, and any loose or dangling clothing should be secured.
A soldering iron is a specially designed tool that heats up a pointy metal tip to about 600°F and is used to warm up the components and melt the solder. Some soldering irons will have adjustable temperature, separate power supplies, and interchangeable tips. Hold the iron on the grip like you would a pencil.
SOLDERING IRON TIPS
The tip of the soldering iron is the pointy part at the end that gets hot. In many irons the tips can be interchanged. The two basic tips referred to in this guide are the standard tip which is just a pointy end piece used for general soldering and through-hole PCB soldering, and a screwdriver or chisel tip, which looks like a flat head screwdriver and is used for surface mount soldering.
WET SPONGE AND BRASS WOOL
A wet sponge is used to wipe the soldering iron tips on to knock off extra solder and oxidized flux. Brass wool is handy when trying to remove thicker layers of oxidized flux or stubborn excess solder. Brass wool can be used with or without a holder.
Flux is a chemical that prevents oxidation on the components during soldering. Flux helps the solder flow better, dissipates heat, and prevents oxidation. In simple wire soldering or through-hole PCB soldering, the flux that is part of the solder is sufficient, but when using a different technique for surface mount soldering, additional flux must be used to protect the components. Rosin flux is preferred for electronics soldering. The easiest application for surface mount soldering is the syringe or brush packaging. Whichever flux you use, be sure it is indicated for electronics use!
Soldering is not possible without solder. Solder is made up of low-temperature melting alloy (typically lead and tin) used for joining less fusible metals. In the case of electronics work, the solder used also has a rosin flux core. Solder does come in many different configurations – with or without flux, lead free or leaded, and various alloys for higher temperatures. The recommended solder for this application is 60/40 lead/tin solder, 0.025in diameter, with 2.2% flux. Any solder you choose to use MUST BE INDICATED FOR USE WITH ELECTRONICS. Typically the solder is held in the opposite hand as the iron about four inches from the end of the solder like a pencil.
WIRE SNIPS AND WIRE STRIPPERS
Wire snips do exactly what their name indicates – snip wire. The snips will be used to trim the excess terminal wires on the components after they have been soldered. Wire strippers are used to remove the insulation from wires and have markings on the tool as to what diameter wire goes where. Some wire strippers have wire snips are a part of the tool, though it is often easier to use a dedicated wire snip.
HELPING HANDS, MAGNIFIER, LIGHT – OPTIONAL
All the following tools are optional. Helping hands are small stands with alligator clips that help hold wires and boards during soldering. Be sure if they are used for this project, the clips are placed on the corners of the board away from any circuitry. Magnifiers can be helpful for those with poor vision up close. Additional lighting can be helpful if the workplace is not bright enough and is recommended when a magnifying glass is being used.