Summary: What is a Soldering Iron and how to use one to join two pieces of metal safely
A soldering iron is a hand held tool used, with the use of solder, for heating two pieces of metal to a working temperature in order to join those two pieces together. All soldering tools and materials seen in this project can be bought by clicking into the images in our tool store to the right of this page.
Soldering irons can come in a gun shaped design which people should find easy to use. The pencil design model is generally used for more delicate types of work.
A soldering iron has a heated element at the tip of a heat insulated handle, normally powered by mains electricity or battery.
The heat tip element works through the process of resistive material having an electrical current passed through it, the same process as an electrical bar fire just not as aggressive or quite so hot.
Before using your soldering iron you will need to go through the process of ‘Tinning’, which is the process of heating up and coating the tip of your soldering tool with a layer of solder. This increases the efficiency of heat transfer from your soldering iron.
For most soldering work which involves electric circuitry, a 15w – 30w device will be suitable, any device more powerful than that might do damage to your proposed piece of work.
If you are considering doing more substantial soldering then a soldering iron which uses a 40w or stronger supply of power will be needed.
Even stronger soldering, such as soldering copper pipes for plumbing can be seen by clicking on the link.
When soldering pieces together you will need the following materials:
Solder: A fusible metal alloy used to join two metal surfaces together. These come in different alloy ratios depending on what type of metals you are trying to solder. Be careful when using solder, there can be some spitting and it will be hot and painful if it makes contact with your skin. Check with your supplier that you have the right kind of solder for the job.

Flux: This is a chemical cleaning agent that helps the flow of the solder when worked with the soldering iron. This product will create smoke when being used which is normal.
Soldering stand: This is used to hold your hot soldering iron when not in use.
A damp cloth to clean dirt from your piece of work.
Soldering is used in many ways but mostly in the areas of electronics, jewellery making and stained glass windows. These other types of soldering may require higher powered soldering irons depending on the two metals to be joined.

When you start to solder you will quickly come to recognise a good solder from bad. It is quite easy to identify. A dull solder usually means that you have not created a solid solder action; this could be due to air trapped between the two surfaces you tried to join. A bright and clean solder surface usually means a successful soldering.
If you are just joining two items together (for example two halves of an electrical wire) then the following procedure should be followed:
The two lengths of wire should firstly be joined by simply twisting them together.
When you are ready to solder, start by heating the wire from below. As heat rises through the wire, wetting the tip of the soldering iron may help with the speed the wire heats as well.
When you are ready to apply the solder, apply your solder just above the iron, once you have reached melting point the solder will flow into the joint area with ease. If not you need more heat.
Continue to apply the solder till you see no more wire visible.
Once you have completed your soldering process you will need to cover the join with an insulated sheath or insulating tape. This can be purchased in different sizes which apply to the thickness of wire you are joining. The insulating tube comes in heat wrap format. Once in place heat, shrink and seal.
See also our project on brazing metals
As always with machinery or devices that create dust, debris or have hot components, DIY Doctor recommends the use of gloves, dust masks and eye protection.
All project content written and produced by Mike Edwards
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