Seasoned DIY enthusiasts may want to take on more daring plumbing tasks like attempting to sweat a copper pipe to use for plumbing fixture replacements.
Sweating or soldering copper pipes is a process used to join copper pipes together to create leak-proof joints. We recommend trying the sweating process on practice pipes first to gain confidence before working on your home plumbing.
Are you ready to learn how to solder your own copper pipes? Read on to learn the eight steps to sweat a copper pipe.
How to Sweat a Copper Pipe
Step 1: Gather Your Tools
Before you begin, be sure to have all the necessary tools lined up and ready to go so that you can avoid plumbing mistakes. You will need specialized tools, safety items, and materials for sweating copper pipes, including:
- Tube cutter
- Practice pipes
- Propane torch
- Emery cloth
- Flame protector cloth
- Fire extinguisher
- Safety goggles
- Insulated gloves
- Wire fitting brush (optional)
- Lead-free solder
- Paste flux or tinning flux
In addition to safety gloves and goggles, you will want to wear a heavy, long-sleeve shirt and hat to protect yourself from any potential burning solder drips.
Step 2: Cut the Pipes and Remove Burrs
Use a pipe cutter to achieve the desired length of your copper pipes. To cut the pipe, follow these steps:
- Place the copper pipe in the tube cutter and tighten the blade until snug.
- Turn the pipe a couple of times.
- Remove the pipe. You should see a groove cut around the circumference.
- Realign the groove with the blade, and tighten it again until it’s snug.
- Twist until the pipe is cut.
After completing the cut, inspect the pipe for burrs. A burr is a ridge of copper shards caused by the cutting tool that can impede water flow if not removed. If you notice burrs, use the pipe cutter’s built-in burr removal tool to shave away the shards.
Step 3: Clean the Pipe’s Mouth
Next, clean the outside and inside of the first inch or two of the pipes and the fitting joint pieces with an emery cloth. To speed up the process, you can wrap the emery cloth around a wire fitting brush. Otherwise, wrap the cloth around your index finger and wipe the mouth of the pipe clean. After cleaning, avoid touching the pipe with your bare hands, as your skin’s oils can disrupt the soldering process.
Step 4: Apply Plumbing Flux
For this step, be sure to wear thick, insulated work gloves to protect your skin from acid. You’ll want to apply a thin layer of tinning flux to the cleaned interior and exterior portions of the copper pipes and fittings. Use an acid or flux brush to apply the flux, and wipe off any excess material with a clean rag.
Step 5: Heat the Flux
Now it’s time to bring out your soldering torch. Before you light the torch, hang a flame protector cloth over every surface within eight inches of your work area, and put on your safety goggles. Once you and your work area are safe, start the propane torch and hold it about two inches from the fitting joint. Pass the flame slowly over the flux-covered areas for 10 to 20 seconds until the flux becomes shiny and melts.
The flux will sizzle and maybe smoke, and the copper’s color will darken. As the acid begins to work, it will create a bondable surface.
Step 6: Connect the Pipes
Keep your gloves on and push the connecting pieces together until sealed. Gently twist the copper pipes to solidify a bond and distribute flux evenly in the joint. Use a clean rag to wipe off any excess flux.
Step 7: Heat the Joint
Next, you will create a seam at the joint by setting your torch to a rosebud flame. A rosebud flame is a lower-power flame that wraps around the entire pipe, bringing the whole pipe up to sweating temperature at once. This flame makes for a cleaner and more even soldering. Use the rosebud flame to heat the joints you created in the previous step.
Step 8: Apply Lead-Free Solder
Finally, you will apply lead-free solder to the pipe joint and allow it to melt around the seam. Keep in mind that some stores still sell leaded solder, and it is essential to use lead-free solder for this project. Hold the lead-free solder at a 90-degree angle to the joint seam opposite the rosebud flame. Then, touch the heated pipe with the solder.
The solder will melt if the pipe is hot enough. If it’s not hot enough, the solder won’t melt, so keep the flame on the joint until the solder melts upon touching the pipe. Once the solder melts, it will flow around the seam and seal the two pipes together. After this step is finished, you have successfully sweated copper pipes!
Complete Your Project With Pride
Once you’ve completed all the steps outlined above, you can turn off your propane torch and gently set it down. Clean up any excess solder with a clean rag, and admire a job well done. Allow the copper pipe to cool for at least one minute before applying any pressure.
If you decide you want to leave this project to the plumbing experts, reach out to A.J. Alberts Plumbing today. We’ll be happy to work with you to schedule timely service.