Knowing basic soldering techniques is useful for repairing or creating your own connections for electronic projects at home. This guide is for a simple wire-to-wire connection. For printed circuit board soldering I recommend following this instructable.

Supplies

The list below is an in depth view of some of the tools and equipment needed to make your experience soldering as painless as possible.

Safety Glasses – Because your eyes are precious.
Soldering Iron – Iron’s come in many forms. I’ll be using a butane powered unit. I recommend something like this if you’re just looking to do a quick fix. Other units can be clunky or require the use of an extension cord to get to certain locations. Butane fuel can be found at any big-box store with a camping isle. It is recommended that an iron be able to reach between 300 to 400 Celsius for proper heating of the solder.
Soldering Iron Stand – This is essential to safety. Simply leaving a hot iron lying around is not ideal.
Solder – A 60/40 Tin to Lead Rosin Core is best for soldering, but as you know, lead can be dangerous. Many brands have substituted Silver and Nickle which will work just fine so long as flux paste is used. (Note: Avoid any acidic solder mainly used for plumbing in copper pipes this will damage electronic connections.)
Solder Flux – Also known as Rosin Paste is highly recommended. This acts as a catalyst in melting the solder. Without using flux, you may find yourself struggling to get the solder to run. (Note: Avoid acid flux, this will damage electronic connections.)
Wire strippers – A good set of wire strippers will help from having to struggle with tough wire insulation.
Brass sponge – A sponge is necessary to keeping your soldering iron clean. A wet sponge will also suffice.
Heat Shrink Tubing – This will allow you to create a watertight seal around your connection. Electrical tape can also be used as a substitute.
Heat Gun – Used to heat the heat shrink tubing. A lighter is also a good substitute.
Third Hand – What is known as a third hand is nice to have when you need some help, but this is not essential. You could always ask someone for help.

Step 1: Safety First!

Above all, the safety of yourself and others is to be taken into considerations when handling any tool. Soldering irons can be extremely hot, so have a clean work area and remove any flammable materials from your workspace. Use a stand to place your soldering iron on to avoid damaging your work surface or burning yourself. Your work area should be properly ventilated from fumes and well-lit for visibility. Always wear your safety goggles.

Step 2: Preparation Is Key

Always start by making sure all your tools are clean and ready to use. To clean, heat your iron and dip the tip into the brass sponge. Once the sponge has cleaned the tip you will want to do what is called “tin” the tip with a small amount of solder. Tinning is a technique that will promote adhesion between two soldered ends, as I will demonstrate in the next steps.

Step 3: Getting the Wiring Ready

This step involves stripping the insulated jacket of your wiring with the wire strippers. Wiring comes in many sizes, or gauges, this wiring comes in 14 Gauge. Take note of the wiring size to avoid stripping part of the wiring underneath the insulation.

Once removed, the simplest method of connecting two wires is to simply intertwine them. Just pressed each end onto the other and twist into one.

To ensure the soldering process goes smoothly, I highly recommend the use of flux paste. Adding some to the joint will save you time and frustration.

Step 4: Getting the Technique Down

The most widely used method of soldering is to simply apply heat to the joint from below with your soldering iron and placing the end of your solder over top using gravity to allow the solder to run down and into the joint.

*Note: If using heat shrink, ensure you have placed your tubing on the wire prior to soldering. Also, the tubing is sensitive to heat, hence "heat shrink", so beware of applying too much heat near the tubing to avoid it shrinking.

Step 5: Insulating the Connection (Heat Shrink)

Insulating your connection will seal any exposed wiring from creating a short in your circuit and possibly starting a fire. Using this watertight jacket will also protect the wiring from the elements.

Once you have soldered your connection, slide the tubing over the exposed wiring and use a heat gun to shrink the tubing over the joint. Electrical tape can also be substituted as an insulator, but beware, electrical tape can unravel itself over time exposing the wiring.