How to use a soldering iron

Soldering is a useful skill to have, whether you plan to use it professionally or for DIY projects. A quality soldering iron is one of the most important tools you'll need for your soldering projects.

This guide will provide a brief overview of how to use a soldering iron. It will give you the basics that apply to most soldering work, as well as tips for specific types of projects.

Although all soldering relies on the same principles, the techniques and tools you use may vary depending on the type of materials you're soldering and the kind of outcome you're intending. On this page, we'll cover step-by-step soldering for wiring, printed circuit boards, stained glass and jewelry.

Here's your introductory guide to using a soldering iron.

The basics

The fundamentals of soldering are mostly consistent across project types. Below you'll find information about the basics of soldering, descriptions of the equipment involved and a basic step-by-step guide for how to use a soldering iron.

1. What is soldering?

Soldering is a technique for joining metal parts together. It involves melting a metal known as solder into the space between two metal components. When this solder cools and hardens, it forms a permanent connection between the parts. Solder acts as a sort of metallic glue that joins elements together.

Joining electronic components may be the most common use of soldering irons. You can also use them on piping for plumbing, engine components, arts and crafts projects and more.

2. What equipment do you need?

This article is about how to use a soldering iron, but the iron itself isn't the only item you'll need. Here's a rundown of some of the supplies you may need to use, including a soldering iron, for a soldering project.

• Soldering Iron: A soldering iron supplies the heat that melts the solder. It consists of a tip, which you apply to the metal parts you want to solder together, and an insulated handle so that you can hold the iron. There are several variations of soldering irons. Often, they are electrical and use an electrical cord or battery. Some also use the combustion of a gas such as butane or an open flame. Some irons allow you to adjust the temperature of the iron.
• Solder: Solder is the substance that melts and forms the bond between the two soldered components. It is a thin wire made of one of several tin alloys. The alloys consist of either tin and lead or tin and copper. Increasingly, lead-free solders are becoming the more popular of these two options. This trend is a response to increased safety regulations as well as the environmental and health benefits of seeking lead-free alternatives. Some types of solder also include flux, a substance that gets rid of oxide layers on metal parts to help the solder adhere better.
• Soldering Station: A soldering station acts as a control station for your soldering iron if you have an adjustable iron. The station has the controls for adjusting the temperature of the iron as well as other settings. You may plug your iron into this soldering station.
• Soldering Iron Stand: You might also use a soldering iron stand, which provides a safe, sturdy place to store your iron when you are not using it. It might also include a place to keep supplies for cleaning your iron.
• Cleaning Pad: It's essential for proper performance to keep your iron clean while you use it. You may use a cleaning pad, steel or brass wool or a damp sponge.
• Safety Glasses: Safety goggles will help protect your eyes in case of accidents and keep fumes from irritating your eyes.
• Fume Extraction Equipment: Fumes created when soldering may be toxic. Fume extraction devices pull fumes from the air to reduce health and safety risks.

Getting set up

Before you begin using your soldering iron, you'll have to make sure that you've taken all the necessary safety measures and prepared your tools.

1. Safety measures

Health and safety should always be a priority when soldering. Soldering involves extreme heat and toxic substances. While it involves certain risks, if you take the proper precautions, soldering is a relatively safe activity.

Before getting started, read the instructions as well as the health and safety warnings that come with all of your equipment to ensure you're using it correctly. When soldering, wear safety glasses and keep all hair, loose clothing and jewelry secured and out of the way of your tools. You may also want to wear safety gloves.

Be sure that you are working in a well-ventilated area or use a fume extraction device. The fumes from flux are toxic. If the solder you are using contains lead, wash your hands after you're done working with it.

2. Cleaning and tinning

For your soldering iron tip to work correctly, it needs to be clean and tinned. Any contaminants or oxidation will decrease the efficiency with which it conducts heat, making your job harder and reducing the quality of your solder joints.

Before you start soldering, clean the tip of your iron by rubbing it against your cleaning pad. If your tip is badly oxidized, you may need to apply a tip reactivator. After cleaning or reactivating it, it should appear shiny rather than dull.

Tinning the tip of your iron involves coating it with a layer of solder. This practice protects the tip from oxidation and improves its ability to conduct heat. Tin the tip immediately before you begin soldering.

In addition to cleaning and tinning the tip of your iron before each soldering session, you should also do so after every two or three joints you solder and at the end of each soldering project. This will extend the life of your soldering iron tips and improve the quality of your soldering joints.

Joining parts

Once you've completed the above steps, you're ready to solder your components together. The techniques you'll use will vary from project to project, but the basic step-by-step instructions are as follows:

1. First, determine the right temperature for your project. Which temperature to use depends on the materials you're joining and the kind of solder you're using. As a general rule of thumb, the best temperature to use is the one that's as low as possible while still being high enough to get the job done. In other words, if the temperature needed to do the job is 370 degrees or above, then set the temperature to exactly 370. This will help extend the life of your tools and avoid damaging any electronic components.
2. Once your iron is heated to the appropriate temperature, pick up the iron by the handle in one hand and hold a piece of solder in the other hand. Hold the hot iron to the place where the two metal components will meet for about a second to heat them up. You want to heat the metal parts, not the solder itself.
3. Then, touch the solder to the heated components. As the solder melts, it will flow into the gaps it needs to fill. Continue to feed in solder until a sufficient amount is melted. While you need enough to form a solid connection, you don't want to have too much solder either. The right amount will vary from project to project. This typically won't take more than a few seconds.
4. Allow the solder to cool. You don't need to take any action to cause it to cool. It will do so on its own and shouldn't take longer than a few more seconds.
5. Check the soldering joint for quality. A good connection will appear smooth, uniform and shiny. Make sure that aren't any problematic gaps between the components or globs of excess solder.

Desoldering

If you made a mistake in your soldering, don't worry. You can undo and fix any problem areas relatively easily. If the problem isn't excess solder, you may be able to resolder over the first joint with new solder.

A more thorough method of correcting a soldering mistake is to reheat the solder you applied and then to use a tool such as a "solder sucker," which is a small syringe-like device that uses vacuum pressure to remove solder. You can also use a solder wick, also called a desoldering braid, which absorbs melted solder by capillary action.

Cleaning up

After you finish a soldering session, clean and tin your soldering iron tip. After allowing the iron to cool, store it in a secure location. To further prevent oxidation, especially if you will not be using the iron for a long time, place it in a sealed container.

Tips for specific soldering projects

Now that we've covered the basics, let's look at how to do some specific types of soldering.

1. How to use a soldering iron for joining wires

You can use a soldering iron to create an electrical connection between two wires. Having a tool, such as a device called a third helping hand, to hold the cables for you is very helpful. A third helping hand consists of a weighted base, metal arms and crocodile clips that hold the wires in place. You can also use a pair of pliers to a similar effect.

1. First, make sure some insulation is stripped off the end of the two wires to expose the metal filaments.
2. Then, twist the filaments of each wire together so that they act more like one solid unit.
3. Next, tin the wires. To do this, touch the tip of the soldering iron to each wire to heat them. Then apply solder until the wire is soaked through. There should be solder throughout all of the filaments but not so much that the cable becomes overly stiff. This will help heat spread throughout the filaments more efficiently and make soldering easier.
4. Mechanically join your wires so that the solder is not the only thing holding them together. To do this, wrap the first wire around the second, leaving enough space to wrap the second wire around the first. The turns of the cable should lay next to one another.
5. Heat the mechanically joined wires with the soldering iron and apply solder. Use enough solder to fill in all the spaces and form a reliable electrical connection.
6. Once the two wires are connected, apply a heat-shrinkable tubing to isolate the wires and keep them shielded from any outside forces. This tubing will shrink under applied heat, helping it to adhere tightly to the wires and creating a form-fitting protective coating.

2. How to solder printed circuit boards

Soldering parts onto printed circuit boards (PCBs) is another frequent use of soldering irons.

1. Start with the tallest components, and solder interconnecting wires last. For through-hole components, place them in the correct holes in the PCB. Make sure they sit flush against the board.
2. Bend the lead of the part slightly to keep it in place.
3. Once the soldering iron has reached the desired temperature, touch it to the pad to heat the lead of the component and the pad. Make sure the temperature is correct. Too low of a temperature can create a joint that doesn't provide an adequate electrical connection. Too high of a temperature can damage the components and board.
4. Then, apply the solder. The solder will flow around the component liquid. Use enough to create a solid connection without gaps but not so much that you're left with excess solder.
5. Pull the iron straight up from the component. The solder joint should form a cone-like shape.
6. Check your joint to make sure that it appears shiny and that there aren't any gaps or too much solder
7. If the solder joint is adequate, cut the excess component lead above the joint.

3. How to solder stained glass

Solder is what holds the individual pieces of glass in a work of stained glass art together. Here's how you use solder on stained glass.

1. Before soldering, make sure the stained glass pieces fit together well and that the glass is clean.
2. Apply copper foil to the edges of the glass because solder won't adhere to glass. This foil should be smooth and even so that the solder flows evenly. You don't need gaps in between the pieces, but solder will be able to fill small gaps.
3. Apply a small amount of flux and then solder to each joint to help hold them in place.
4. Then apply a layer of flux to all seams. The coating should be even and light but enough to cover all foil.
5. Start soldering about a quarter of an inch from the edge of your piece. Touch the heated iron lightly to the copper foil and feed in the solder. Move the iron and solder along the foil seam. If the solder seam appears flat, try going slower and using more solder. If it's spilling over onto the glass, try going faster. Getting this part right takes practice.
6. Once you're done with the first side of your, flip it over carefully while holding it from the edges near the middle of the piece. Apply a small amount of flux and then solder this side.
7. To finish the outside edges, tin them by making sure all copper foil gets covered with solder. Alternatively, you can apply a U-channel came - a small, U-shaped metal piece - for a more framed look.

Some other tips include only using solid-core solder rather than acid-core or rosin-core solder as well as not applying heat for too long in any one area as this can cause the glass to break.

4. How to solder jewelry

You can solder jewelry using an open-flame torch, which can provide higher temperatures, but can also do so with a soldering iron. The precise techniques vary depending on the kind of item you want to make, and there's more room for creativity with jewelry soldering. Search online for instructions on how to make specific pieces or experiment and create your own designs.

For example, you can bend silver, copper or other types of wire to form rings. You can solder the two ends of the bent wire to create a single ring, or solder multiple rings together to make a necklace or bracelet. Heat the wire where you want to join it and then apply solder.

Some helpful jewelry soldering supplies include high-quality wire cutters and a third helping hand tool.