What Is Soldering?
Soldering is a joining process in which different types of metals are joined together by melting solder. Solder is a metal alloy, usually made of tin and lead, that is melted with a hot iron. The iron is heated to temperatures above 600 degrees Fahrenheit, which is then cooled to create a strong electrical bond.
When you disassemble an electronic device with a printed circuit board, the components are attached using soldering techniques. Soldering is the process of joining two or more electronic parts by melting the solder around the joint.
Solder is a metal alloy and when it cools it creates a strong electrical connection between parts. Although soldering can create a permanent connection, it can also be reversed using a desoldering tool as described below.
The good thing about soldering is the fact that it doesn’t take much to get started. The following are the basic tools and materials you will need for most of your soldering projects.
1. Soldering Iron
A soldering iron is a hand tool that plugs into a standard 120V AC outlet and is heated to melt solder around electrical connections. This is one of the most important tools in soldering and can come in a few variations such as pen or gun shape.
For beginners, it is recommended to use the pen soldering iron in the 15W to 30W range. Most soldering irons have interchangeable tips that can be used for various soldering applications. Be very careful when using a soldering iron as it can heat up to 896’F which is extremely hot.
2. Soldering Station
A soldering station is a more advanced version of the standalone basic soldering post. If you plan to solder a lot these are great as they offer more flexibility and control. The main advantage of a soldering station is the ability to precisely adjust the temperature of the soldering iron, which is beneficial for a number of projects.
These stations can also create a more secure work area as some include advanced temperature sensors, alarm settings, and even password protection for security.
3. Soldering Iron Tips
At the end of most soldering irons is a replaceable part known as a soldering tip. There are many variations of this tip and they come in a wide variety of shapes and sizes. Each tip is used for a specific purpose and offers a distinct advantage over another. The most common tips you use in electronics projects are the conical tip and the chisel tip.
- Conical Tip Used in precision electronics soldering because of the fine tip. Because of its pointed end, it’s able to deliver heat to smaller areas without affecting its surroundings.
- Chisel Tip This tip is well-suited to soldering wires or other larger components because of its broad flat tip.
4. Brass or Conventional Sponge
Using a sponge will help keep the soldering iron tip clean by removing any oxidation that builds up. Tips with oxidation tend to turn black and stop accepting solder as it was when it was new. You could use a conventional wet sponge, but doing so will shorten the life of the tip due to expansion and contraction.
Also, a damp sponge will temporarily lower the tip temperature when it is wiped off. A better alternative is to use a brass sponge as shown on the left.
5. Soldering Iron Stand
A soldering iron stand is very simple, but very useful and practical. This stand prevents the hot iron tip from coming into contact with flammable materials or accidentally injuring your hand. Most soldering stations come with this built-in sponge and also include a sponge or brass sponge to clean the tip.
Solder is a metal alloy material that is melted to create a permanent bond between electrical parts. It is available in both lead and lead-free variants, with diameters of 0.032 “and 0.062” being the most common. Inside the solder, the core is a material known as flux that helps improve electrical contact and its mechanical strength.
Lead-free rosin core solder is most commonly used for electronic soldering. This type of solder is usually made from a tin/copper alloy. You can also use leaded 60/40 (60% tin, 40% lead) rosin core solder, but this is becoming less and less popular for health reasons. If you use lead solder, make sure you have adequate ventilation and wash your hands after use.
When purchasing solder, be careful NOT to use acid core solder as this can damage your circuitry and components. Acid core solder is sold in hardware stores and is mainly used for installation and metalworking.
As mentioned earlier, solders come in a few different diameters. The thicker diameter (0.062 in) solder is good for soldering larger joint faster, but it can make soldering smaller joint difficult. Because of this, it’s always a good idea to have both sizes on hand for your different projects.
7. Helping Hand (Third Hand)
A helping hand is a device that has 2 or more alligator clips and sometimes a magnifying glass/light attached to it. These clips will help you hold the items that you want to solder while you use the soldering iron and solder. A very helpful tool for your maker space.
8. Soldering Safety
Now that you know what tools and materials you will need, it is time to briefly discuss ways of staying safe while soldering.
Soldering irons can reach temperatures of 800 ° F. So knowing where your iron is at all times is very important. We always recommend using a soldering iron stand to avoid accidental burns or damage.
Make sure you are soldering in a well-ventilated area. When the solder is heated, fumes are released which are harmful to the eyes and lungs. It is recommended to use a fume extractor, which is a fan with an activated charcoal filter that absorbs harmful solder smoke. You can visit locations like Integrated Air Systems for air filtration systems.
It is always a good idea to wear safety glasses if you accidentally splash hot solder. Lastly, be sure to wash your hands when you are done soldering, especially if you are using lead solder.
Tinning The Tip
Before you can start soldering, you need to prepare your soldering iron by tinning the tip with the solder. This process helps to improve the heat transfer from the iron to the object to be soldered. Tinning also helps protect the tip and reduce wear.
Step 1: Begin by making sure the tip is attached to the iron and screwed tightly in place.
Step 2: Turn on your soldering iron and let it heat up. If you have a soldering station with an adjustable temp control, set it to 400′ C/ 752′ F.
Step 3: Wipe the tip of the soldering iron on a damp wet sponge to clean it. Wait a few seconds to let the tip heat up again before proceeding to step 4.
Step 4: Hold the soldering iron in one hand and solder in the other. Touch the solder to the tip of the iron and make sure the solder flows evenly around the tip.
You should tin the tip of your iron before and after each soldering session to extend its life. Eventually, every tip will wear out and will need replacing when it becomes rough or pitted.
How Does Soldering Work?
The solder is melted using the heat of an iron connected to a temperature controller. It is heated to temperatures above its melting point of about 600 degrees Fahrenheit, causing it to melt and then cool, creating the solder joint.
In addition to creating strong electrical joint, solder can also be removed with a desoldering tool.
Solder is a metal alloy used to create strong, permanent bonds. like copper connection in circuit boards and copper pipe joints. It can also come in two different types and diameters, lead and lead-free, and can also range from 0.032 “to 0.062”. Inside the solder, the core is the flux, a material that is used to reinforce and improve its mechanical properties.
What Metals are Used?
Filler metals used in soldering used to be lead-based (lead solder). Due to regulations, lead-containing solders are increasingly being replaced by lead-free solders, which can consist of antimony, bismuth, brass, copper, indium, tin, or silver.
Which Flux Can be Used for Soldering?
Occasionally there will be impurities such as oil, dirt, or oxidation at the point of connection. The flux prevents oxidation and can sometimes dry clean the metal. The flux used is rosin flux which aids in mechanical strength and electrical contact of the electrical connections. Sometimes it is also possible to apply a wetting agent to reduce surface tension.
Types of Soldering
There are three types of soldering that use higher and higher temperatures, which in turn lead to increasingly stronger joints:
- Soft soldering (90 °C – 450 °C): This process has the lowest filler metal melting point of all the soldering types at less than around 400°C these filler metals are usually alloys, often containing lead with liquidus temperatures under 350°C. Because of the low temperatures used in soft soldering, it thermally stresses components the least but does not make strong joints and is then therefore unsuitable for mechanical load-bearing applications. It is also not suited for high-temperature use as this type of solder loses strength and melts.
- Hard (silver) soldering (>450 °C): Brass or silver is the bonding metal used in this process, and requires a blowtorch to achieve the temperatures at which the solder metals.
- Brazing (>450 °C): This type of soldering uses metal with a much higher melting point than those used in brazing and soldering. Similar to brazing, however, the metal to be bonded is heated and not melted. Once both materials are heated sufficiently, you can place the solder between them, which will melt and act as a binder.
How To Solder
To better explain how to solder, we’re going to demonstrate it with a real world application. In this example, we’re going to solder an LED to a circuit board.
Step 1: Mount The Component: First, insert the cables from the LED into the holes in the circuit board. Flip the board over and bend the cables outward at a 45 ‘angle. This will help the component make a better joint with the copper pad and prevent it from falling out while soldering.
Step 2: Heat The Joint: Turn your soldering iron on and if it has an adjustable heat control, set it to 400’C. At this point, touch the tip of the iron to the copper pad and the resistor lead at the same time. You need to hold the soldering iron in place for 3-4 seconds in order to heat the pad and the lead.
Step 3: Apply Solder To Joint: Keeping the soldering iron on top of the copper pad and lead, touch the connection with your solder. IMPORTANT Do not touch the solder directly with the tip of the iron. You want the joint hot enough to melt the solder when touched. If the joint is too cold, a bad connection is formed.
Step 4: Snip The Leads Remove the soldering iron and let the solder cool naturally. Do not blow on the solder as this can result in a bad joint. After cooling, you can cut the extra wire from the cables.
A proper solder joint is smooth, shiny and looks like a volcano or cone shape. You want just enough solder to cover the entire joint but not too much so it becomes a ball or spills to a nearby lead or joint.
How To Solder Wires
Now it’s time to show you how to solder wires together. It is recommended that you use helping hands or some other type of clamping device for this process.
First, strip the insulation from the ends of both wires that you are soldering together. When the wire is stranded, twist the strands together with your fingers.
Make sure your soldering iron is fully heated and touch the tip to the end of one of the wires. Hold it by the wire for 3-4 seconds.
Holding the iron in place, touch the wire with the solder until it is completely coated. Repeat this process on the other wire.
Hold the two tinned wires on top of each other and touch both wires with the soldering iron. This process should melt the solder and coat both wires evenly.
Remove the soldering iron and wait a few seconds for the solder joint to cool and harden. Use heat shrink tubing to cover the connection.
The good thing about using solder is the fact that it can be easily removed using a technique known as desoldering. This is useful when you need to remove a component or correct your electronic circuit.
To desolder a joint, you will need solder wick which is also known as desoldering braid.
- Place a piece of the desoldering braid on top of the joint/solder you want to be removed.
- Heat your soldering iron and touch the top of the braid with the tip. This heats the solder under which it is then absorbed by the desoldering braid. You can now remove the braid to see that the solder has been extracted and removed. Carefully touch the braid when heating it or it will get hot.
Optional – If you have a lot of solder you want to be removed, you may want to use a device called a solder sucker. This is a handheld mechanical vacuum that sucks up hot solder with a press of a button.
To use, push down the plunger on the end of the solder sucker. Heat the joint with your soldering iron and place the tip of the solder sucker over the hot solder. Press the release button to suck up the liquid solder. Push the plunger down to empty the suction cup.
Uses of a Soldering Iron
A soldering iron is a hand tool used to heat solder, usually from an electrical supply, at temperatures above the melting point of the metal alloy. This allows the solder to flow between the workpieces to be joined.
This soldering tool consists of an insulated handle and a heated, pointed metal iron tip. Good soldering is influenced by how clean the tip of your soldering iron is. To ensure cleanliness, a user holds the soldering iron firmly and cleans the soldering iron tip prior to soldering components or making the soldered joint.
In addition to the soldering iron, solder suckers are an important part of the soldering structure. When excessive solder is applied, these small tools are used to remove the solder, leaving only what you want.