What Gauge Solder Do I Need for a Soldering Iron?

Plumbing

• Traditionally, plumbers have used a 50/50 -- 50 percent tin, 50 percent lead -- solder for joining pipes. But the lead in the solder can leach into the drinking water, so lead-free solder is now used for all drinking water applications. Use No. 16 gauge (1/16 inch) solder for general plumbing purposes. Plumbing solder is often melted with a butane or propane torch rather than a soldering iron.

Electronics

• For electronics work, you’ll want to use a rosin-core solder. Rosin, also known as resin, is a noncorrosive flux that can dissolve some of the impurities that are present on the components, so that the solder can create an effective bond. No. 16 gauge solder works well for heavier electronics work, such as wiring tube-type equipment. For fine soldering, such as circuit board work, you’ll want to use a smaller gauge solder, such as No. 22.

Model Railroading

• Model railroaders solder train tracks as well as electronic components. You’ll want to use a rosin-core solder for both applications. For soldering the electronic components, follow the guidelines for choosing the correct gauge solder for electronics – namely, using a finer gauge solder. No. 22 gauge is a good choice. You’ll need thicker solder for the tracks -- No. 19 gauge, which is 0.040 inches (1.01 mm) thick, or even one that is slightly larger.

Jewelry Making

• Very fine silver solder – No. 28 gauge or smaller – is used in jewelry making. You can find it in wire rolls or in sheets. Many hobbyists use “easy-flo” silver solder, which has a low melting point and is easy to work with.