Electrical wires are part of every electrical circuit. They carry current (in the form of electrons) that power all electrical and electronic devices we use today.

But, why is solder used for joining electrical wires? Solder is used in joining electrical wires to create a permanent bond between them Also, solder is made of a conducting material that allows current to flow between electrical wires. There are many different types of electrical wire, as well as solder that is used to join them. 

Main purpose why solder is used for joining electrical wires

Electricity (electrical current) is the flow of electrons in an electrical circuit. It is what powers every electrical device from Lights, Motors, Microwaves, Televisions etc.

This flow of electrons requires a path to travel in a circuit to get from one component/device to the next. However, electrons can only flow through conducting materials like metals. An insulator like plastic will inhibit the flow of current. 

Electrical wires are composed of conducting materials that allow electrons flow in a circuit. 

There are many different types of electrical wires that range in materials, core diameter, and number of strands. 

Where does solder play its part?

Some of the time you will need to join two pieces of electrical wires to complete the path to allow current to flow. 

Solder is used to create a permanent connection between these two wires while allowing current to still flow.

A deeper look at solder

So, what is solder?

Solder is a material that in most cases is an alloy which has the ability of joining electrical wires. 

A soldering iron is needed to metal the solder that can then adhere to the pieces of electrical wire being joined together.

Different types of solder used for joining electrical wires

There are many different types of solder available, that are made using a number of different conducting materials. 

Traditional solder was lead based (made with lead). However, the use of lead based solder proved very dangerous as it creates fumes that are detrimental to a person’s health.

It can cause health problems that relate to the reproductive system, digestion, memory, and muscle/joint pain.

Due to this, regulations have been put in place to replace lead based solders with Lead-Free solders. 

These lead-free solders contain materials such as Antimony, Bismuth, Brass, Copper, Indium, Tin and Silver. 

They come in a variety of diameters as well. The larger diameters are better for larger joints, while smaller diameters are suitable for smaller hard to get joints. 

Is solder used to join wires in electronic applications as well?

Electronics is a sub-category of Electrical Engineering which also deals with the flow of currents. 

Electrical applications are of higher voltages and currents, electronic applications deal with lower voltage and current applications. 

While the wires used in electronics might vary due to the lower currents, solder is still used as a bonding agent to join wires. 

The only thing that will vary will be the type of solder used.

Best solder for joining electrical wires?

Since there are so many different types of solder available, which is the best for joining electrical wire.

The most commonly used is a lead-free rosin core solder which is typically a Tin/Copper alloy. 

If you opt to use a lead based solder, the 60/40 (60% tin, 40% lead) rosin core solder is your best option. 

However, when using lead based solders, remember to follow safety practices such as having proper ventilation, and wearing a face mask.

Other considerations to make when choosing solder to join wires, is to make sure they are not acid core as they can damage your circuit and components. 

Is there a substitute for solder to join electrical wires?

There might be instances where you have run out of solder, and need to join two electrical wires. 

Is it possible to join two wires without using solder?

Yes. You can join electrical wires if you do not have solder. 

Common ways to do so are:

• Twist the stripped ends of wires together or
• Use electrical tape to create a bond between the stripped ends. 

However, if the electrical wires carry high currents, it is not advisable to make bonds using the methods mentioned above. 

These should only be used for temporary purposes only, like if you are testing the functionality of the circuit. 

They should never be used as a permanent solution. 

Advantages of using solder to join electrical wires

The most common advantages of using solder to join electrical wires is that it creates a long lasting bond, and it allows current to flow as it is a conducting material. 

It is a better option compared to the alternatives that I mentioned above (twisting the wires and electrical tape). Using these temporary methods does not create a good connection between wires and has the potential of falling apart. 

Using solder will avoid these downfalls.

It also has many other advantages which include:

• Low power required
• Low process temperature 
• No thermal distortions and residual stresses in the joint parts
• High variety of materials may be joined
• Low level of skill required 

What is used to melt solder to join electrical wires?

So, solder is the ‘glue’ that is used to connect electrical wires together. But,what is the process of joining wires?

Soldering is the process that is used to join electrical wires. The solder needs to be melted in order to join two pieces of electrical wire. It needs to be heated up to temperatures around  441 degrees fahrenheit ( 227 degrees celsius). 

The way it is heated to these temperatures so it can melt is by using something known as a soldering iron. A soldering iron is a very useful tool used a lot in the Electrical and Electronic Field. 

Is solder only used for joining electrical wires?

You might assume that solder and soldering is only used for joining electrical wires and wiring components in electrical and electronics applications. 

While it’s mainly used in these fields, solder and soldering is very versatile and can be used in other applications as well. 

Other soldering applications include:

• Plumbing
• Jewelry
• Sheet Metal work
• Stained glass work

Since the sole purpose of solder is to be the ‘glue’ between two pieces of metal, applications where metal pieces need to be joined together can use solder.

Can solder be used for welding applications?

I mentioned above that solder can be used for applications where metal pieces need to be joined. 

However, this is only applicable for smaller pieces of metal. 

There are instances where larger pieces of metal need to be connected. Solder will not be suitable for these applications. 

This requires a process known as welding. Welding is similar to soldering in its processes. It uses a filler bonding material (similar to solder) and high heat to melt it to join two pieces of metal together. The main distinction is that welding uses higher temperatures and melts the base metal as well. 

Is solder used for DC and AC applications when joining wires?

We now know that solder helps create strong bonds and help current flow between two wires that are joined together. 

But, there are two types of current used to power devices ; Alternating Current (AC) , and Direct Current (DC).

Alternating current is charge that changes its directions periodically. It is most commonly found in electrical applications. 

Direct current, on the other hand, is a charge that only travels in one direction. It is commonly found in electronic applications. 

Solder can be used in joining wires that carry both AC and DC types currents. 

The only considerations that need to be taken into account is how much current travels through these wires. Higher currents will require larger diameter wires. Therefore, larger diameter solder will be needed to create a stronger bond, and be able to handle these high currents. 

Is the bond of solder permanent when joining electrical wires?

Solder is used to create a ‘permanent’ bond between electrical wires. But, is this bond really permanent?

The bond that is created by solder between electrical wires is permanent but reversible. 

The removal of solder between electrical wires and components is known as Desoldering. 

There might be a faulty wiring in a circuit, or you might have soldered the wrong wires together. You do not have to worry as you can remove the solder and start again.

Tools used to desolder include:

• Solderwick
• Desoldering pump

For a comprehensive guide on how to desolder check this article.

Tips and Tricks on how to solder electrical wires

Using solder to join electrical wires can be cumbersome and annoying at times. But, there are tips and tricks you can use to make the process less stressful. 

These tips and tricks will also help you create stronger bonds that will last longer and let current flow better.

Check the video below on how to solder electrical wires.

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