Chapter | 12 Soldering 209 TOO FAR, TOO FAST Whoooaaaahhh! Steady there! We've jumped the gun a little here, in an effort to show you how the soldering of components to a printed circuit board works. We now need to step back and con- sider soldering ­ and indeed, solder itself ­ as theoretical and practical principles. We also need to learn how to actually sol- der ourselves. It's not difficult ­ but there is a knack to it (some say an art, even) that some people don't always find too easy to learn. That's the aim of this final chapter of the book ­ to teach us enough about solder and soldering to be able to do it ourselves. WHAT IS SOLDER? Solder is a metallic compound that has a low enough melting point ­ somewhere around 200°C ­ that it can be heated by small hand-tools (called soldering irons) till it melts and thus joins other metals (in electronics terms: component leads, copper track) together when it cools and re-solidifies.