How to choose a soldering station? How to make beautiful welds?


In the breadboard course we saw how to prototype your circuit, replace components easily, and choose the wires to connect them.

But once your circuit is complete, it’s time to solder it.

In this course we’ll look at what soldering is, what materials you need to make one and how to do it.

What is a weld?

Soldering is a technique used to melt a metal between two metals, in our case component pins or bonding wires. This soldering allows the two pins or wires to be connected, so that a voltage can be passed between them.

Why do welding?

We could ask ourselves, why solder and not leave our circuit on a breadboard, for example?

The breadboard has many advantages when it comes to prototyping, but the closer you get to the end of the project, the more it has to be replaced by a PCB. The breadboard makes it easy to change the position of components and move wires around.

In the real world, however, your circuit can move and vibrate, which can unplug cables. Using a breadboard therefore makes your project more fragile. What’s more, the aim of an electronic circuit is to be as small as possible. With a breadboard, this is generally larger than it could be with a PCB board, for example.

Soldering therefore reduces the size of your circuit while consolidating it.

Tools needed for welding

To make a weld, you first need a soldering iron. It’s a bit like a big pen, with a nozzle at the end that heats up and melts the metal. You’ll also need a metal wire, which is lead-free solder and will enable you to make the weld between the two wires or components you wish to connect together.

There are plenty of other useful tools for making welds. We’ll go into more detail in the course.

Soldering iron

The soldering iron with the metal wire is the main element in the soldering process. So it’s important to choose the right one. There are several types of soldering iron: fixed-temperature, variable-temperature and soldering stations.

A) Fixed-temperature soldering iron

The fixed-temperature soldering iron is often sold with a pen-like handle and a power cable at the end. This is often the least expensive of the soldering irons, and therefore the one you turn to when you’re just starting out.

Some only come with a small sponge and a plastic holder for your iron. We advise you to check that these two items are sold with your iron, as the sponge is very useful for wiping off excess metal at the end of the nozzle, and the iron holder can be used to rest your hot iron between two welds, for example.

Fixed-temperature soldering irons are great for starting out, but they often heat up to a high temperature, which can be dangerous for even the most fragile components. Fixed-temperature soldering irons come in a range of wattages, from 12W to 40W. We recommend an iron powerful enough to heat up quickly. A 25W iron will be sufficient for soldering.

b) Temperature-adjustable soldering iron

Unlike fixed-temperature soldering irons, adjustable-temperature soldering irons have a knob to adapt the temperature to your needs.

You’ll find adjustable soldering irons in two different forms: as a pen with the feed wire like the fixed-temperature soldering iron, or as a soldering poster.

c) Soldering stations

Soldering stations are the highest-quality soldering irons available. They consist of a holder for the soldering iron, a support for resting it between two welds, a sponge and a temperature variator.

A soldering station will work much longer than a soldering iron with the power cord at the end, as they are often more robust.

The metal to weld

There are two different types of metal for soldering: leaded and lead-free.

Many people prefer lead solder because it’s easier to work with. What’s more, it has a lower melting point, which means the metal will melt well before damaging your components.

However, during the smelting process, lead solder gives off toxic odors that can be hazardous to your health. We therefore recommend lead-free solder. This is a mixture of tin, copper, silver or zinc.

In all cases, you need to work in a well-ventilated room, and avoid breathing in solder fumes.

Protect yourself from smoke!

To protect yourself from the smoke generated by your welding, you can use an air extractor. You place the nozzle over your weld, and the smoke is directed towards the nozzle instead of your nose. You can find one for as little as 60 euros.

It’s an item we strongly recommend if you regularly weld!

Soldering accessories

A) Third hand

A third hand is a plastic tool made from crocodile clips. It allows you to hold the wires you wish to solder, freeing your hands to hold the soldering iron and solder wire.

Crocodile clips are all adjustable with small knobs, which can be quite time-consuming to set up, but guarantees you a better result. Buy a metal one rather than a plastic one if you want it to last longer.

B) Wire strippers


To solder wires together, you’ll need to strip them. Stripping means removing the plastic part (insulation) from the wire, leaving only the metal part.

You need to do this just on the part of the wire to be soldered. There are two types of wire strippers: manual and mechanical. Mechanical wire strippers save time, but are less reliable in the long term and damage faster than manual wire strippers.

Once we’ve seen all the tools you need to make a good weld, we’ll take a look at the different steps involved in making a good weld.

The welding steps

  1. First, make some room in your workspace.
  2. Take out your soldering iron
  3. Take out the connecting wires you need
  4. Cut the wire insulation with a pair of pliers or a pair of hand pliers.
  5. Heat up your soldering iron and place it on its stand, not directly on the workspace.
  6. Prepare your third hand if necessary, or your components to be soldered.
  7. Turn on your vacuum cleaner to avoid breathing in the smoke
  8. Once the iron is hot, you can start welding with the metal
  9. As soon as the weld is complete, clean your iron’s nozzle and turn it off.
  10. Leave your iron to cool for 20-25 minutes before putting it away.

How can I check if my weld is successful?

A solder joint is successful if it’s solid, doesn’t contain too much metal and connects the two wires or components. For solidity, you’ll have to wait and see. For beauty, you can see whether you’ve used too much metal or not.

As far as the connection between the two components is concerned, you can use a multimeter for this. In fact, there’s an option with a loudspeaker logo on some multimeters that allows you to emit a sound if the current is flowing properly by touching both sides of your solder joint. Take a look at our multimeter course for more information.

How to protect your weld?

To protect your weld, you can use a glue gun and apply it to the weld. The glue will harden and protect the weld from chafing or shock. You should do this only after the solder is cold and working. You won’t be able to remove the glue to re-solder your weld, so be sure!

What to do if the weld fails?

If you’ve messed up your soldering, the connection isn’t right or it’s not strong enough, there are solutions. Tools such as desoldering pumps and desoldering braids can help you remove the metal.

A) Desoldering pump

The desoldering pump is used to suck off bits of hot metal from your solder to remove it. It’s a squeeze pump, and locks in place when the air is expelled.

When you press the trigger, a spring pushes the plunger back, causing all the solder to be sucked into the plunger chamber. When you press the piston release again, it pushes out all the weld that has been removed. For this to work, the solder must be hot and liquid.

B) Desoldering braid

Desoldering braid is another way of removing solder. It is a copper wire that has been braided into a coil.

Hold the soldering iron over the braid and press lightly. The solder will continue to melt and fill the gaps between the mesh and the braid. Removing the braid should also remove the solder. You can then cut off the part of the braid you’ve used.

Caution: Do not remove the braid if the weld is cold!

If the braid has cooled down, it’s attached to the board and you risk tearing off components by removing it. Re-heat the solder with your soldering iron to loosen it.

Weld or braid, which to choose?

Both the pump and the welding braid are useful for removing welds. However, they have different uses. When components overheat, use the desoldering pump. To remove residual solder, use soldering braid.