Digital technologies/Soldering/Soldering- Beginner

What is Soldering?

Soldering is a process often used when working with electronics. It consists of melting one metal to connect two or more metal pieces. This connection not only creates an electrical connection, but it also secures a component in place.

We will be going over two different situations where soldering is used. The first being when soldering two different wires together and the second is when soldering a component to a perfboard or a PCB. A perfboard is a rigid board which has a grid of holes drilled into it. Each hole is surrounded by a copper pad onto which you can adhere solder. A PCB is a printed circuit board. They are similar to perfboards except that the components are connected using a conductive material built into the board.

Safety When Soldering

• When Soldering be sure to wet the sponge being used inorder to avoid burning it or ruining the tip of the iron
• Don’t leave the iron unsupervised and on
• Long exposure of the iron to the PCB and other electronic components will lead to them burning
• Don’t touch the iron
• Allow the solder and board to cool before handling

Types of Soldering

Through-hole-technology (THT)

• Through-hole-technology (THT) soldering means to solder components that have leads that will go through holes inside a protoboard or PCB.

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Surface mount device (SMD)

• Surface mount D soldering is when you will solder a component to the surface of a PCB. This type of soldering is typically used for smaller components and chips.

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What to not do when Soldering

What is needed:

• Soldering iron
• Solder (preferably lead free)
• Components you want to solder
• Vent fan

Optional items:

• Solder wick
• De-soldering tool
• Soldering mat

Soldering two wires together

Soldering two wires is the best way to practice soldering at the very beginning. There are two types of wire, either stranded or solid core. Both have a metal core wrapped in a plastic covering. To see the metal, you need to expose the core by removing the plastic. There are special tools to do this called “wire strippers”. However, it is possible to do the same thing with scissors. A video on how to strip the wire is available here.

Procedure

1. Grab a few wires, strip 1 cm off each end and bend each end in a U shape.
2. Crimp the two wires together with a pair of pliers.
3. Hold the soldering iron like a pen. Heat the two wires for 1-2 seconds and then flow solder on the connection. The goal is to heat the connection not the solder. Once you see the solder flow evenly throughout the connection, remove the solder and soldering iron.
4. Allow the connection to cool, this usually takes 20-30 seconds. During this time, avoid moving the wires

Soldering to a board

1. Place the lead (metal stick coming from component) or wire through the hole in the perfboard or PCB.
2. Holding the soldering iron like a pen, heat the copper pad and lead with soldering iron until the solder begins to flow and forms a strong connection. Remove solder, and then the soldering iro. This process should take only a few seconds.
3. Allow for the connection to cool

Do's and Don'ts

Remember to:

1. Select the correct temperature
   • 700F (370C) for through hole components and wires
   • 600F (315C) for surface mount components
   • Higher temperatures can damage
2. Clean the tip between uses
   • It’s better to use the gold wool to clean the tips rather than the sponges
3. Wet the sponges before use
   • If the sponges are used dry, they burn and leave residue on the tips
4. Tin the tip when you are using the iron
   • Add a small amount of solder to the iron to keep it from oxidizing when you place it in the holder

Do not:

1. Do not leave the iron on. Leaving the iron can cause the tip to burn and will ruin in the iron over time
2. Do not file the tip. The tips have a protective coating the will get ruined
3. Don’t touch the mat or any plastics with the iron. A thin plastic film will form on the iron which will inhibit soldering. This includes heat shrink tubing.