What are different watt soldering irons for?

If you've ever shopped for a soldering iron, you'll know that there's a wide range of soldering irons available from 15 watts to 60 watts and sometimes higher. This can present you with a head-scratching choice when shopping for one, you can choose from basic 15-20 watt irons, mid-range 25-30 watt irons or general use 40-60 watt irons. So which one should you choose?

Common sense would dictate that a higher wattage will result in higher temperatures, so if you are soldering only very small objects or wires, then a lower wattage will suffice, however, this thinking is wrong and can be a potentially costly mistake.

The temperature of a soldering iron is almost a by-product of its wattage. That's not to say that temperature is not important, but what is more important is the iron's ability to maintain its operating temperature during operation, and that is where higher watt soldering irons fare much better.

All soldering irons are hot enough to melt solder, but contact between the soldering iron and surface to be soldered can suck the heat right out of an iron's tip. This will result in a requirement to hold the iron in place for a longer period to keep the solder melted while it transfers to the wire. While all of this is happening, heat will also transfer along the wire potentially causing damage to the cable's flex and any nearby components.

A higher watt soldering iron will have the power to maintain the heat of the tip. This will melt the solder and have the job done before the wire has a chance to transfer heat and cause damage.

Which wattage you should choose when purchasing a soldering iron depends on what you are using it for. If during your hobby you are likely to be soldering a range of different materials, an iron with variable temperature control would be a worthwhile choice. As for soldering irons with a fixed watt rating, only you can decide. If the tool is to sit in your toolbox just in case the odd wire brakes, then a basic, lower wattage soldering iron will do just fine, however, if you are planning to use it to create good, reliable joins during the construction of a layout, investing in a higher wattage could be a wise decision.