Can You Solder Copper Wire? Here’s How!

Bringing copper wires together through soldering may be necessary to fix electronics or used for a wide range of metal art projects. Soldering is the process of using a melted filler metal (solder) to join your desired pieces of metal. You can use the soldering method on copper by using the right type of solder and working carefully to rejoin the wires. 

Read on to follow our step-by-step guide in successfully soldering copper wire. Abiding by each step is necessary to secure the wires correctly and safely complete the task. Your safety should be the top priority when soldering or using similar power tools. 

Acquire Soldering Equipment 

There are only a few items you will need to properly solder copper wires together. While the process does not require many items, finding quality materials and using them correctly is essential to finish the job properly. 

You will need the following items to solder copper wire: 

• Soldering Iron: This handheld tool heats up to melt the solder around the copper wiring. Make sure you follow the instructions on the specific iron for temperature settings and proper usage. Soldering tools for electrical applications should be in the 25-30 W range. 
• Solder: For best results, use electrical-grade solder because it is stronger and creates a more secure connection than other solders. This type of solder is specific to electrical applications as others can damage the wire components.  Look for solder that states it uses rosin-core flux. 
• Sponge: You will need a damp sponge to clean the soldering iron tip before use to avoid any interference from debris. 
• Wire strippers (if necessary): Insulation should be removed from the area to access the wires directly. 
• Heat shrink tubing: This will be used to reinsulate at the end if desired. If you plan to do this, the tubing will need to be placed at one end of the wire before joining them together. 

With limited materials needed, soldering at home is a relatively inexpensive and straightforward process. Soldering materials are commonly found in kits that provide you with all the necessary materials to solder in various applications properly. 

Source: Maker’s Space, ToolBoom

Adhere to Important Safety Considerations 

Soldering irons can reach temperatures as hot as 800° F (400° C) and should be handled carefully. Because you are working with dangerous equipment, safety precautions should be a top priority before starting any project.

The most important safety considerations to make when soldering include: 

• Use PPE: You should wear some form of protective eyewear to prevent any solder from spraying during the process. 
• Solder in a ventilated area: Fumes released from melted solder can be toxic when inhaled in high concentrations. A well-ventilated area will prevent potential irritations. 
• Check wattage and power settings: Ensure that your soldering iron is set to the proper wattage and heat settings when working with copper wire. The individual tool should come with instructions for which settings to use. 
• Use soldering stand: To avoid any contact with the soldering tip, the iron should be placed back in its stand. Any contact with a work surface can be dangerous. 
• Wires should be disconnected: The copper wires should never be plugged in or be in use when soldering. Ensure there is no electrical current flowing. 

Working carefully will not only keep you and those around you safe but also result in the best soldering and effectively join the wires together. 

Source: Stony Brook University, Oregon State University

Strip Wire Insulation (If Necessary) 

The copper wiring needs to be fully accessible to use solder in joining the materials together effectively. This means that any wire insulation needs to be removed from the soldering area. If you need to remove insulation, you will use your wire strippers at this point in the process. 

Most wire strippers will have guidance on the tool itself for varying wire sizes. You will place the wire in the marked hole, clamp down, and slide it through the tool. This will strip the insulation from the wire. We recommend removing a little more insulation than required to ensure that the soldering will not come in contact with the insulation. 

Source: Helpful DIY

Intertwine Copper Wiring to Rejoin Materials 

When rejoining copper wires, they must be intertwined and reconfigured so the wires are all closely touching. To do this, carefully spread each end of the wires you plan to rejoin. They are typically coiled tightly, but you can slightly fan them to look like the bristles on a broom. 

Once both sets of wires are spread out, you can place them within each other, so the wires are intertwined and embedded within one another. You can then twist the wires together to create a firm and stable connection between both sides. You can check out how to join the wires in this video. 

This brings the wires back together but is not a permanent fix, making the soldering steps below necessary. 

Heat Soldering Iron 

Follow the instructions on your iron for proper heating. Solder melts at temperatures between 360-370° F (180-190° C), but the iron can reach much higher temperatures. The temperature at which you set the iron will depend on the model of iron, specifically the tip. Tips with larger surface areas and greater power may not need to be set as high to melt the solder efficiently. 

After the soldering iron has heated to its necessary temperature, the most crucial step is to wipe the tip on your damp sponge. This sponge needs to be damp to remove any potential debris left on the iron and avoid any sponge burning. If the tip is not wiped, oxidation can occur from buildup at greater levels. 

Source: Metcal

Apply Soldering To Copper Wire 

After doing all this preparation, you can now apply the soldering to the copper wire. To do this, follow these steps in order: 

• Secure wires for soldering: You only have two hands, which will be used to hold the solder and the iron. Secure both sides of the rejoined wire so they won’t move when touched with the iron. They should be propped up off the workspace so you can have access to the area under the wires.  
• Place soldering iron under the wire: Touch the tip of the soldering iron to the copper wires. This will heat the wire to allow your solder to melt. Your solder will be applied opposite from the iron (on top of the wire).  
• Melt solder: First, place the solder on the tip to allow for melting. You will then move the solder up and down the top of the wire to cover it in a thin layer. Using too much solder will make it difficult for the electrical current to pass through the wire with the additional resistance. The soldering iron will not move throughout this process. 
• Remove excess solder: If there is clumping or excess solder, you can reapply the iron to melt the solder and allow the excess to melt off. This should be done after cooling to examine the results. 

Source: TWI, Science Buddies 

Reinsulate Wiring with Heat Shrink Tubing 

After the soldering has completely cooled, you can reinsulate the area with heat shrink tubing. While this step is not required, it does give the wire a finished look and prevents any wire exposure. You will want to find tubing that is close in size to the wires you used and make sure that you use a longer piece than the desired area for coverage. 

Heat guns should be used to shrink the tubing around the wires. Move the heat gun back and forth to evenly distribute the heat over the entire piece. Do this until the tube has snuggly secured itself around the formerly exposed area. 

Soldering Copper Wire Efficiently 

While soldering copper wire is a fairly simple task, following each step carefully is necessary to keep you safe and ensure that you do the job right the first time. The most important thing to remember is using your soldering in moderation. You want to cover the area enough to ensure wires are reconfigured but not prevent the electrical current from moving smoothly.