'[2025 Edition] Complete Soldering Guide for Electronics | Basics and Tips Even Beginners Won't Fail'

If you’re starting with electronics, soldering is an unavoidable skill. While it may seem difficult at first, it’s a technique that even beginners can reliably master by understanding the correct procedures and tips.

In this article, I’ll explain in detail everything from soldering basics to practical techniques, common failure cases and their solutions, incorporating my own experiences.

What is Soldering?

Soldering is a technique of melting metal solder with heat to electrically connect electronic components and circuit boards.

Purpose of Soldering

• Electrical Connection: The primary purpose is to electrically connect components
• Physical Fixation: As a secondary effect, it also fixes components to the board
• Ensuring Reliability: When properly soldered, stable electrical signals flow

Soldering is not meant to provide strength to the joint, but rather to establish electrical connections. Therefore, it’s important not just to consider appearance, but to create a state where electricity flows correctly.

Necessary Materials and Tools

• We recommend considering ease of use and researching before purchasing your own equipment.
• I’ll introduce examples of tools that I actually found easy to use.

Basic Set (Absolutely Necessary)

Useful Additional Tools

Lead-Free vs. Lead-Based Solder Differences

There are two types of solder: lead-free and lead-based (eutectic solder). Currently, due to environmental regulations, lead-free solder has become mainstream, but it’s important to understand the characteristics of each.

Comparison Table

Which Should You Choose?

Tips for Beginners Using Lead-Free Solder

Caution: When using lead-based solder, always wash your hands after work and don’t work near food or drinks. Lead is toxic to humans.

How to Identify Good Soldering

The quality of soldering can be judged by appearance.

Three Characteristics of Good Soldering

Characteristics of Bad Soldering

Basic Soldering Procedure

Here I’ll explain the procedure that’s hard to fail even for beginners.

STEP 1: Preheat the Soldering Iron

Preheat the soldering iron for 2-3 minutes before use.

• For temperature-controlled models: Set to 320-350°C
• Iron tip shining silver indicates proper temperature
• If blackened, clean with cleaner

Point: Don’t work in places where air conditioner or fan wind directly hits. Temperature drops easily.

STEP 2: Fix the Board and Components

Place components on the board and temporarily fix with masking tape.

• Fix firmly so components don’t move
• Component leads (lead wires) should stick out slightly on the back side of the board
• No need to be too long as you’ll cut them later

Note: Ideally you should cut lead wires to proper length beforehand, but for DIY, the method of cutting later for ease of fixing is also acceptable.

STEP 3: Clean the Iron Tip

Clean the iron tip with a cleaner just before soldering.

• Sponge type: Wipe the tip with a lightly moistened sponge
• Wire type: Insert into wire to remove dirt

Important: If the tip is blackened by oxidation, solder will be repelled and likely fail.

STEP 4: Apply Flux (If Necessary)

If solder flow is poor or you want to ensure success, apply a small amount of flux to the pad and lead wire.

• Flux evaporates easily, so work quickly after application
• For beginners, applying every time reduces failures
• Contains rosin, so always close the lid tightly after use.

STEP 5: Heat the Pad and Lead Wire

This is the most important step.

1. Lay the iron tip flat

   • Contact the side of the tip (silver part) broadly to the pad
   • Don’t hold it vertically, tilt it about 30-45 degrees

2. Heat both pad and lead wire simultaneously

   • Use the tip to sandwich the contact point of pad and lead wire
   • Heating time is about 3-4 seconds

Tip: Laying the tip flat increases contact area and efficiently transfers heat. This is the biggest point of successful soldering.

STEP 6: Melt and Flow the Solder

Once the pad and lead wire are sufficiently heated, add solder.

1. Lightly touch the solder

   • Don’t touch the solder to the iron tip, touch it to the contact point of pad and lead wire
   • Confirm solder melts and flows smoothly

2. When solder forms Mt. Fuji shape, remove solder first

   • Keep the iron still touching
   • Amount of solder should cover the entire pad (be careful not to use too much)

3. Wait 1-2 seconds, then quickly remove the iron

   • Removing slowly creates “spikes”
   • The trick is to remove quickly

STEP 7: Cooling and Confirmation, Cut Excess Leads

Wait 5-10 seconds for the solder to solidify.

• Moving before solidification causes “cold solder joints”
• Once solidified, cut excess lead wires with nippers
• When cutting, cut 1-2mm above the solder base

Finally, check:

• Is it Mt. Fuji shaped?
• Is the surface smooth and glossy?
• Is it firmly attached to both pad and lead wire?

STEP 8: Continuity Check

• After soldering is complete, always perform a continuity check.
• Before turning on power, use the continuity mode of a multimeter to check if each pin and pad is properly connected and there are no shorts.
• If you hear a buzzer sound during measurement, it’s normal; if not, there may be a broken connection.
• Check important circuits like power lines and GND especially carefully, and only turn on power if there are no problems.
• This simple step can prevent circuit troubles.

10 Tips to Avoid Failure

Here are practical tips summarized.

What to Do When Soldering Fails

Everyone fails sometimes. Deal with it calmly.

Solder Removal Method

Common Troubles and Solutions

Soldering Safety Measures

Since soldering irons reach high temperatures (over 300°C), safety measures are essential.

Safety Precautions

Recommended Practice Methods for Beginners

The more you practice soldering, the better you get.

Practice Steps

Summary: Anyone Can Solder Once They Get the Hang of It

While soldering may seem difficult at first, it’s a technique that even beginners can definitely master by understanding the correct procedures and tips.

Key Points of This Article

• Characteristics of good soldering: Mt. Fuji shape, smooth surface, secure attachment to pad and lead wire
• Most important tip: Lay the tip flat and heat pad and lead wire sufficiently
• If you fail: Remove with solder wick and calmly redo
• Safety first: Beware of burns, ventilation, fire

Once you can solder, the range of your electronics projects will greatly expand. Even if you fail at first, practice many times and master it.

I hope your electronics life becomes more enjoyable and fulfilling.

Reference Videos

The following video is very easy to understand and highly recommended for reference.

• Ichiken/ICHIKEN [Permanent Edition] Explaining How to Solder