Soldering Basics

Making a breadboard circuit permanent.

Soldering joins two metal parts — usually a component leg and a copper pad — by melting a metal alloy (solder) that flows into the joint and hardens into a solid electrical connection.

• Heat both the component leg and the pad together for a second or two before feeding in solder — the solder should melt from the joint's heat, not the iron's.
• A good joint looks shiny and forms a smooth cone; a dull, lumpy joint is a "cold joint" and may not conduct reliably.
• Always work in a ventilated area, use a stand for the hot iron, and let joints cool untouched for a few seconds.

Practice on a cheap prototyping board before soldering anything you care about — the technique takes a few dozen joints to feel natural.