What is Soldering and How to Do it?

Soldering is one of the most fundamental skills required in electronics. But, before you go ahead with soldering, it is always wise to have proper knowledge about the process. This post will explain everything from the basics of soldering to the process of doing it.

What is Soldering?

Soldering is a process of joining components permanently to a printed circuit board. An alloy of lead and tin (63% tin and 37% lead), is used to fix a component pin or leg to the copper track of a circuit.

Solder is a low-melting, fusible metal alloy, and is used to create a permanent bond between metal work pieces. Generally, solder can be made from tin and lead, or from silver or brass. Silver and brass solders are used to join less fusible metals at higher temperatures.

What Materials are required for Soldering?

Following materials are required for soldering:

1. A soldering iron
2. Rosin core solder
3. Stand to hold the hot soldering iron when not in use
4. Sponge
5. Solder braid
6. Prototype board
7. Steel wool or fine sandpaper
8. Crocodile clips

Preparations for Soldering:

Before starting the process of soldering, one should take the following points into account:

1. Place the soldering iron in its stand and plug it in. This is done because the iron becomes very hot, and can cause damage to equipment, if not kept in the stand.
2. Wait for the soldering iron to heat up.
3. Moisten the sponge.
4. Wipe the tip of the iron on the damp sponge. This will clean the tip.
5. Melt a little solder on the tip of the iron.
   • This is called tinning, and it will help the heat flow from the iron’s tip to the joint.
   • The solder should flow onto the tip, producing a bright shiny surface.
   • If extra solder flows onto the tip, clean it by wiping it on the wet sponge.
   • Re-tin the tip if it has gone dull. This usually occurs when the soldering iron has not been used for quite some time.
   • Check the manufacturer’s instructions related to tinning the tip.
6. The soldering iron tip should always have a shiny silver color. If it is black and pitted, it is recommended to replace it with a new one.

How is Soldering Done?

It is very important to follow the steps given below while soldering:

1. Clean the surface on which soldering need to be done. Remove any wax, paint, or oil with steel wool, a solvent, or fine sandpaper.
2. Heat the connection for a few seconds with the tip of the soldering iron. Make sure that you hold the soldering iron near the base of the handle like a pen.
3. Keep the soldering tip on the connection, and apply the solder. Solder will flow into and around well heated connections. To ensure a strong connection, you should use right amount of solder.
4. Once the solder has flowed where you want it to be, remove the tip from the connection. Remove the solder, and then the iron.
5. Allow the solder to cool.
6. Avoid overheating the connection, as it might damage the electrical component you are soldering.
7. Wipe the tip of the soldering iron on a moist sponge to clean it.
8. Unplug the soldering iron when not in use.

Safety Precautions

You are required to follow some safety precautions while soldering. Here are some of them:

• A soldering iron can heat to about 400°C, which can cause severe injury or start a fire, Thus, it is always recommended to use it carefully.
• Make sure that the soldering iron is unplugged when it is not in use.
• Avoid touching the tip of the soldering iron to a power line. If a power cord is touched by a hot iron, there is a serious risk of electric shock and burns.
• Always put the soldering iron in its stand when not in use. Never put the soldering iron on your work bench.
• The smoke from the melted solder is mostly from the flux, and can be harmful for your health. Hence, avoid inhaling it.

Following the aforementioned steps will help you solder efficiently and safely. Sierra Assembly Technology is into designing Printed Circuit Boards (PCBs) for over 3 decades now, and can help you with your queries related to soldering and designing a PCB.