A Guide for Soldering Electronics

My introduction to soldering electronics coincided with a rough patch in my marriage due to appliance failure.

When my wife and I got married in 2014, in our quest to save money, we purchased a used dryer. Sadly, it didn’t work for long. The savings didn’t make up for dozens of hours of frustrating repair work and hundreds of dollars in new parts.

Naturally, I was too stubborn to listen to my wife and buy a new dryer. So for several weeks, our laundry room looked like a bomb hit an appliance factory as I struggled to diagnose and fix the problem.

The main control board was one of the issues, and a new one cost more than $200, which is what I paid for the whole machine. I decided to remove the control board and attempt a DIY repair.

A few YouTube videos later, I realized I needed to learn how to solder electronics. I bought the necessary equipment, identified the failed circuit on the control board and reconnected it with solder in less than 10 minutes. The dryer started working, and my marriage was saved — at least until six months later, when the dryer broke again.

On the bright side, I learned how to solder electronics. That’s come in handy many times since my dryer adventure.

Here, I’ll tell you everything you need to know about soldering electronics.

What Is Soldering?

Soldering bonds two or more metal objects together by melting a different kind of metal and using it as a kind of glue. This bonding metal, usually tin and lead, is called “solder.” It comes as wire on a spool, heated to its melting point by an electric tool called a soldering iron (or soldering gun).

Soldering is most commonly used to join wires in electrical circuits, copper pipes in plumbing systems and electronic components on circuit boards. Soldering electronics is more skill-dependent than other kinds of soldering, and requires specialty equipment.

For DIYers, most electronics soldering involves appliance repairs. You’re trying to join tiny electronic components with electrically conductive solder to complete a circuit so the device can function again.

When Would You Solder Electronics?

Every time I’ve needed to solder electronics, it’s been on an appliance that’s stopped working. Chances are it’ll be the same for you.

Modern appliances feature electronic circuit boards that tell the device what to do when the user presses various buttons. These boards rely on delicate electrical connections formed by solder.

Sometimes connections can overheat when drawing lots of current, melting the solder. When this happens, chances are it’ll break the electrical connection of that particular circuit, and your appliance will stop working.

That’s when a little DIY boldness comes in handy. A broken circuit often leaves a small sign, like a burn mark. Use this mark to trace the damaged circuit, and you can quickly repair it using a little solder and a steady hand.

Tools and Materials for Soldering Electronics

Soldering electronics requires a few specialty tools and materials. Here’s what you’ll need:

• Soldering iron for fine work: Resembling an extra-large pen with a power cord, these fine-tipped soldering irons feature variable temperature control, making detailed soldering easier.
• Soldering iron stand: Holds the hot tip of your soldering iron away from all surfaces to avoid fire risk. A simple one comes with some soldering irons.
• Supply of 1-mil.-dia. 60/40 solder: Thin wire made from 60% tin and 40% lead.
• Prototype board: An empty circuit board with rows of holes and copper pads that allows easy solder connections. The idea is to solder various electrical components to the board and create a circuit of your choice.
• Fine sandpaper: I use 180-grit to clean all electrical connections before soldering them together. This ensures a much stronger bond.
• Micro wire cutters: These are used for cutting excess wire on fine electrical circuits.
• Copper solder braid: Fine braided copper that absorbs unwanted solder from a circuit board when heated with your soldering iron.
• Damp sponge: A quick way to clean molten solder from the end of your soldering iron as you work.

How To Solder Electronics

Identify the circuit you need to connect. Clear a workspace, then clean the tip of your soldering iron with a damp sponge. Place your iron in its stand and plug it in.

Once it’s hot, add a little solder to the tip of the iron to protect it and improve heat transfer. This is known as “tinning” the tip. Hold the heated and tinned tip of your iron against the electronic component you’ll be bonding.

Allow several seconds for the iron to heat the component, then press the tip of the solder wire against the electronic component and the tip of your iron. If you’ve heated the component enough, the solder will melt and flow into it, forming a strong bond within seconds.

Common Mistakes When Soldering Electronics

• Using solder that’s too thick: Electronics circuits are almost always small and fine. Using solder that’s too thick in diameter can easily lead to too much molten metal pooling on the circuit board and “circuit bridging,” where pins (small devices that hold wires in place for easier soldering) you didn’t intend to join are soldered together.
• Not heating the solder enough: Solder becomes soft quickly when in contact with a hot soldering iron, but that doesn’t mean it’s ready to join your components together. It needs to be fully molten to form a strong, continuous bond.
• Heating the solder too much: Do so, and the metal will become a liquid that’s too runny to do the job. Instead of connecting your circuit, it’ll flow out across the circuit board and make a mess. As you heat your solder, it will become visibly shiny as it reaches a liquid state. This shininess is a sign it’s ready to bond.

Safety Tips for Soldering Electronics

• Always wear eye protection;
• Work in a well-ventilated space;
• Don’t wear loose clothing;
• Tie back long hair;
• Wear a long sleeve cotton shirt and close-fitting heat-resistant gloves to avoid getting solder on your skin;
• Wear close-toed shoes;
• Clear the area of anything flammable;
• Keep a fire extinguisher within reach;
• Don’t lean directly over the solder as you work, to avoid breathing in fumes;.\
• Unplug your soldering iron when not in use;
• Always keep your soldering iron in its stand, never on your bench;
• Wear an anti-static wrist strap when handling circuit boards.