How to Solder Wires

By Lee Wallender

Updated 10/29/19

Soldering Wires

Phil Gradwell/ Flickr / CC BY 2.0

Learning how to solder wires is more important than ever. Homeowners are increasingly taking on repairs of home appliances such as dishwashers and refrigerators. When you know how to solder, small appliances like electric teapots and simple electronic items no longer need to be discarded when they malfunction. With patience and a little practice, you can learn how to solder wires for repairs, as well as for fun projects.

In this simple project, you will solder together the exposed ends of two plastic-coated stranded copper wires. No special skills are needed to perform this task. Because the materials are so inexpensive, you will have ample opportunities to practice on scrap wires before making your final solder joint.

Project Metrics

  • Working Time: 5 minutes
  • Total Time: 20 minutes
  • Skill Level: Beginner
  • Materials Cost: $25 to $50

Tools and Supplies You Will Need

  • Soldering iron
  • Soldering iron tips
  • Sponge and water
  • Soldering iron stand
  • 60/40 rosin core solder
  • Rosin paste flux
  • Heat shrink tubing
  • Heat gun
  • Wire stripper
  • Eye protection

Instructions

In lieu of purchasing separate soldering components, you may wish to buy a soldering iron station that includes a soldering iron, stand, and a tip cleaner. Since the entire station plugs into an outlet, strain is reduced on the soldering iron cord since the cord does not have to run directly into the outlet. This is important for the delicate hand movements you make when soldering.

Leaded 60/40 solder, composed of 60-percent tin and 40-percent lead, has long been used for soldering and is safe if properly handled. For the utmost in safety, choose lead-free solder, composed of 99.3-percent tin and 0.7-percent copper.

  1. Prepare a Safe Working Space

    Make sure that your work area is well-ventilated, especially when working with lead-based solder. Because the tips of soldering irons can range between 600 and 800 degrees Fahrenheit, work on a non-flammable surface since molten solder can drip. If working with lead-based solder, be sure to thoroughly wash your hands after working with the solder. Use eye protection whenever working with solder.

  2. Strip the Wires

    Strip away 1/2-inch of the plastic coating from the wires with the wire stripper. Try not to leave too much or too little of the plastic coating. Stripping away too little plastic coating will hinder soldering. Stripping away too much plastic coating will expose an excessive amount of copper wire and require you to use more heat shrink tubing. Be sure to use the correct gauge on the wire stripper so that you do not accidentally cut away strands of wire.

  3. Add the Heat Shrink Tubing

    Find the smallest diameter tubing that will fit over the plastic-coated wire. If you choose tubing that is too large, it will not shrink down to the correct size. In terms of length, the tubing should cover the splice, plus another 1/2-inch on each end. Slip the heat shrink tubing onto the wire and put it down the wire about a foot for now.

  4. Join the Wires

    Gently flay the individual strands of wire. Push the wires toward each other, interlocking the strands. Loosely twist the meshed wires. If you twist the wires too tightly, the solder will not be able to penetrate. Yet the joint should still remain smaller in diameter than the heat shrink tubing.

  5. Position the Wires

    Position the wires so that they are elevated over the work surface. Wires that lay flat may get stuck to the surface by the solder. Alligator clips or even household metal spring clamps can be fashioned to elevate the wires.

  6. Add the Rosin Flux

    Carefully rub a small amount of the rosin flux paste to the joined wires so that all of the copper is covered. The rosin flux will help draw the solder into the meshed strands.

  7. Prepare for Soldering

    Plug in and turn on the soldering iron. Unroll about six inches of solder so that the end is exposed and ready to use.

    As the soldering iron heats, rub the tip across a wet sponge to remove any previous oxidation. For a new soldering iron heating up for the first time, this is not necessary.

  8. Solder the Wires

    Touch the heated tip of the soldering gun to the wire joint. Hold the tip firmly in place for a few seconds to heat up the wire. Touch the exposed end of solder lightly to the wire joint. The heat should cause the solder to instantly melt and draw into the meshed strands.

  9. Shrink the Tubing

After the solder has fully cooled, slip the heat shrink tubing over the joint. Make sure that it is evenly positioned. Run the heat gun over the tubing until it constricts completely.