This is the most fundamental skill needed to assemble any electronic project.

There is an accompanying video to show some of these topics listed below.

You should use a soldering iron with a power rating of between 15-25 watts for most project work. A higher wattage does not necessary mean that the iron runs hotter, it means it can cope with larger joints.

The simplest soldering irons don't have any form of temperature regulation but are an ideal general-purpose iron for most users.

A temperature-controlled iron has a built-in thermostatic control, to ensure that the temperature of the bit is maintained at a fixed temperature. Some irons have a bimetallic strip thermostat which gives an audible "click" in use.

If soldering a lot of static-sensitive components (e.g. CMOS chips or MOSFET transistors), then a soldering iron with static-dissipative materials would be advisable. This ensures that static does not build up on the iron itself. These may be described as "ESD safe" (electrostatic discharge proof). Otherwise take the usual anti-static precautions when handling the components.

It's useful to have different diameters or shapes of bits (soldering iron tips), which can be changed depending on the type of work in hand. These are often iron-coated to preserve their life. Do not try and clean these by abrasive means, as you will reduce their life expectancy.

Soldering Iron Tip

The tip should be small enough so that the joint being soldered can be easily seen, but large enough to quickly transfer the heat required raising the joint temperature to the solder melting point.