How to Sweat Copper Pipe Joints

What You'll Need
Emery cloth
Brass brush
Necessary copper fittings
Lead-free solder
Propane torch

Sweating copper pipe joints is another way to say soldering copper pipes. This process intimidates many do-it-yourselfers; however, it is not very difficult. The propane torch sometimes deters do-it-yourselfers, but when used properly it is an irreplaceable tool. For this project, you will need a number of tools and materials. All of the tools and materials are available at your local home improvement store. 

Step 1—Turn Off the Water

Before you begin working with pipes, you need to make sure that the water is cut off. Since you are sweating the pipes, the water is probably already off. However, you should double check to be sure. 

Step 2—Clean the Copper

The most important part of sweating the pipes is to make sure that they are clean. Copper can have residue left on it that makes the soldering not as effective. Using the emery cloth, thoroughly clean the inside and outside of the pipes. You should go about 2 or 3 inches up the pipe. 

The copper fittings also need to be cleaned. The outside of the fitting is probably clean; however, it won’t hurt to run the emery cloth over it. Use your brass brush to clean the inside of the fitting. Don’t forget this part. Your soldering job will be compromised if the pipe or the fittings aren’t clean.

Step 3—Apply Flux

Soldering flux is going to draw the solder into the seam. You will apply the flux to the outside of the pipes and the inside of the fittings. Some do-it-yourselfers are tempted to simply bend the copper pipe into the desired shape as opposed to using elbows and nipples. This is illegal and does not meet the code standards. You can achieve any shape using nipples and elbows. These fitting are readily available at any home improvement store. They come in a variety of sizes to fit your pipes perfectly. 

Make sure that you apply enough of the flux to generously coat the pipe and the fittings.

Step 4—Solder the Joints

Turn on the torch and apply the heat to the seam you want to solder. Leave the heat on the seam for about 30 seconds before you add the solder. You will notice that the flux will begin to drip. That is an indication of the pipe being hot enough for the solder to work properly. It is important that you use lead-free solder. In fact, solder with any lead content is absolutely illegal and will cause your work to fail the code standards. 

Add the solder to the seam. The solder will melt and the flux will suck the metal into the seam. This will create a perfect bond. For a professional looking job, use a rag to wipe the dripping solder from the pipe. 

Step 5—Check Your Work

Let the pipe cool and turn on the water. The pipes should work perfectly.