Wire-to-Wire Soldering
Soldering two wires together is one of the most basic tasks necessary when creating any electrical project or circuit. In this guide, you will learn how to create a strong insulated joint between two wires.
Resources, Tools & Materials
| Type | Name | Description |
|---|---|---|
| Resource | Wire Soldering Guide | Everything you need to know to solder two wires together! |
| Tools | Soldering Iron | Standard soldering iron with fine soldering tip |
| Tools | Hot Air Reflow Gun | Comes with the large (blue) soldering iron stations |
| Tools | Helping Hands | Good for holding components while you work |
| Tools | Wire Snips | Flush cutters good for snipping wire |
| Tools | Wire Strippers | For removing insulation from wires |
| Tools | Brass Sponge | Use this to clean the tip of the soldering iron |
| Materials | Solder | Fine stranded (~0.6mm) lead/tin with rosin core |
| Materials | 24 AWG Wire | Stranded, Single Lead |
| Materials | Heat Shrink Tubing | Helps electrically insulate solder joints |
Safety
- Soldering irons and hot air reflow guns get hot! Even if they are unplugged, they can still be hot enough to burn you. Always hold them by their plastic handles and set them on their appropriate stands.
- Don't leave a soldering iron or reflow gun unattended.
- If you burn yourself, run the burn under cold water for 30 seconds, gently dry, and apply a small amount of burn gel to the affected area and cover with a bandaid (burn gel and bandaids are located in the first aid kit in the kitchen). If you have any questions or the burn seems severe, alert a lab director immediately.
- If soldering for prolonged periods of time, use a fume extractor to ventilate solder fumes.
- Wash your hands throughly with soap and water after handling leaded solder.
Guide
 Before turning on the soldering iron, check to make sure you have a fine (pointed) soldering tip on the iron. |  To change the soldering tip, first make sure the soldering iron is off and completely cool. Unscrew the metal cover and replace the tip. |  Turn the soldering iron on and allow it to heat up. Adjust the heat to 480 degrees (if necessary). |
 Use the wire snips to trim a 6” piece of 24 AWG stranded wire. |  Strip ~1/4“ of insulation off both ends of the wire. |  Press the soldering tip into the brass sponge several times. |
 The brass sponge removes oxidation from the tip. |  Melt ~1” of solder on the tip to tin the tip of the iron. |  Use the edge of the tip (not the point of the tip) to heat the wire. Then apply solder to the heated wire and let it flow. |
 The entire exposed wire should be completely tinned with solder. Repeat this with the other end of the wire. |  Cut a ~3/4” piece of heat shrink tubing and slide it onto the cut wire. |  Place one end of the wire in the helping hands. Hold the soldering iron in your dominant hand and use your other hand to overlap the other end of the wire. |
 Run the edge of the soldering iron over the two wires (no additional solder is necessary). When you see the solder flow together, remove the iron and hold for a few seconds while it cools |  Slide the heat shrink tubing over the solder joint. Turn on the hot air reflow gun and turn up the air flow and temperature to the max settings. Hold the air nozzle ~2” away from the tubing and quickly move it back and forth to apply heat to the tubing. |  Turn off the hot air reflow gun and place it back on the station (it will begin its cool down process automatically). Test your joint by pulling on it. Make 2 more of these solder loops by repeating this entire process. |
Tips
- If the soldering iron temperatuer screen says “SE” there is a chance that the soldering iron has a broken temperature sensor. Please put a sticky note on the soldering iron and report it to a lab assistant.
- Pull on the solder joint -before- heating the heat shrink to make sure that you have a strong joint.
- Remember to let the soldering iron and reflow gun cool down before returning them to the shelves.
Additional Resources