Soldering two wires together creates a strong, permanent electrical connection.
To solder two wires, you typically strip the insulation from the ends, tin the wire strands (making them easier to work with), mechanically join them, apply heat from a soldering iron, melt solder onto the joint, and then insulate the connection, often using heat shrink tubing.
Here is a step-by-step guide:
Essential Tools & Materials
Before you begin, gather the necessary items:
- Soldering Iron: Choose one appropriate for the wire gauge.
- Solder: Rosin-core solder is common for electronics and electrical work.
- Wire Strippers: To remove insulation cleanly.
- Heat Source (for heat shrink): Heat gun, lighter, or even the side of the soldering iron tip (carefully).
- Wire Holders or Helping Hands (Optional): Makes holding wires steady easier.
- Solder Wick or Solder Pump (Optional): For correcting mistakes.
- Safety Glasses: Always protect your eyes.
- Ventilation: Work in a well-ventilated area or use a fume extractor.
Step-by-Step Soldering Process
Follow these steps for a successful soldered joint:
1. Prepare the Wires
- Carefully strip about 1/2 inch to 1 inch of insulation from the end of each wire using wire strippers. Ensure the wire strands are clean and not damaged.
2. Add Heat Shrink Tubing
- Take a little bit of heat shrink tubing and slide it over the ends of one of the wires. Choose tubing that fits snugly over the finished joint but is large enough to slide easily over the wire before soldering. Slide it far down the wire, away from the area you will be soldering. You cannot add the heat shrink after the wires are joined and soldered.
3. Tin the Wire Ends
- Tinning involves applying a small amount of solder to the bare wire strands. This helps make them easier to work with and ensures a better connection with the solder later.
- Heat the bare wire strands with the soldering iron tip.
- Touch the solder to the heated wire (not the iron). The solder should flow into the strands.
- Repeat for the end of the second wire.
4. Mechanically Join the Wires
- There are several ways to join tinned wires before soldering:
- Twisting: Twist the tinned ends together tightly.
- Hooking: Bend a small hook on each tinned end, hook them together, and crimp firmly.
- Western Union Splice (Lineman's Splice): A strong method where ends are wrapped around each other after hooking.
- Choose a method that creates a solid mechanical connection before soldering.
5. Solder the Joint
- Heat the mechanically joined wires with the tip of the soldering iron. Heat the wires themselves, not the solder.
- Once the wires are hot enough (solder will melt on contact), touch the solder to the heated wires.
- Let the solder flow freely around the joint, covering the tinned strands completely. You need just enough solder to cover the joint, not excessive blobs.
- Remove the solder, then remove the soldering iron. Allow the joint to cool and solidify without disturbing it. A good solder joint will look shiny and smooth, not dull or lumpy.
6. Insulate the Joint with Heat Shrink
- Once the solder joint is cool, slide the heat shrink tubing you added earlier back over the soldered connection.
- Apply heat using a heat gun, lighter (briefly, keeping the flame moving), or the side of the soldering iron tip (again, carefully and quickly) to shrink the tubing tightly around the joint, providing insulation and strain relief.
Quick Reference Table
| Step | Action | Purpose |
|---|---|---|
| 1. Preparation | Strip wire insulation | Expose wire for connection |
| 2. Add Heat Shrink | Slide tubing onto one wire | Prepare for insulation after soldering |
| 3. Tinning | Apply solder to wire ends | Make them easier to work with; improve flow |
| 4. Mechanical Join | Twist or hook wires | Provide structural strength before soldering |
| 5. Soldering | Heat joint, apply solder | Create electrical connection |
| 6. Insulate with Heat Shrink | Slide heat shrink over joint, apply heat | Protect and insulate the connection |
By following these steps, you can create durable and reliable soldered connections between two wires.
