Several years ago, I worked with my electrical engineer brother-in-law, Ryan Davis, on an article about how to turn an old-timey radio into an MP3 player

It’s an easy weekend project, but one of the skills you’ll need to have to complete it is knowing how to solder. 

Soldering (pronounced SAW-DER-ING) is used to connect two metal objects together by melting a filler metal called soder between them. Solder has a low-melting temperature and it also turns back to a solid within seconds, making it the perfect “glue” for piecing together small metal bits. 

Soldering is like welding, but with this difference: in welding, you melt the metal objects you wish to connect together; in soldering, you’re using a filler metal to join the metal objects. 

If you decide to take up any sort of hobby involving electronics, you’ll need to know how to solder. With soldering, you can make robots, radios, amplifiers, and a whole host of Arduino projects. 

While soldering might look difficult and intimidating, it’s surprisingly easy and forgiving. 

Below Ryan helps walk us through the basics of this DIY skill.

The Tools You Need to Solder

Soldering Iron.A soldering iron is what melts the solder. You don’t need anything fancy here. A decent soldering iron will set you back $20 to $30. 

Solder.Solder is a metal alloy made of tin and lead (~60% tin/40% lead). Solder used to fuse electrical components has a rosin flux core. When you heat up solder with your soldering iron, the rosin melts first, and flows around what you want to solder, removing surface oxidation, and priming the surface for stronger intermetallic bonds. 

For most electrical projects, you don’t need very thick solder. Wire with a .032 inch diameter works best.

Wet Sponge. The tip of your soldering iron will oxidize as you work with it. That rust on the tip will block the flow of heat from the soldering iron which will in turn prevent you from making a clean solder. That’s why before each soldering connection you make, you want to use a wet sponge to clean off the tip. A lot of soldering irons come with a little holder for your wet sponge. You’ll know your tip is clean when it’s nice and shiny.