How to Join Copper Pipe

Step by Step Instructions on how to Solder Copper Pipes to Make the Perfect Leak free Joint

By Mark J. Donovan

If you have a small plumbing project that requires joining copper pipes read on. This article will explain the process of ensuring leak free soldered joints.

First, cut the copper pipe to the desired length preferably using a copper pipe cutter. A hack saw will also work but it does not produce as clean a cut.

After cutting the pipe, use a small file to take off any burrs in the inside edges of the copper pipe.

Do not use the file to smooth out the outside edges of the copper pipe.

Next, use emery cloth or a very fine grit sandpaper to sand the outside edge of the copper pipe. The end of the copper pipe should have a beautiful shine after you rub it with the emery cloth. After sanding it lightly wipe it down with a clean dry rag.

Repeat this process for the copper fitting and the other length of copper pipe.

Now apply flux onto the copper pipe lengths where you just sanded them. Also brush flux on the inside of the copper fitting.

Next slide the pipe sections into the copper fitting to join the copper pipe sections. Note that it is critical that you keep all the copper pieces clean. Do not lay them down on a dirty floor, bench, etc.

Fire up your propane torch and heat the copper pipe fitting. Do not direct the torch flame onto the copper pipe sections. Heating the copper fitting draws the solder into the joint.

Joining copper pipe

While directing the torch flame onto the copper fitting place the rod of solder next to the fitting where the pipe ends connect into the fitting. When the fitting is hot enough the solder will melt and be drawn into the fitting. As the solder begins to flow move the rod of solder around the ring of the joint to ensure a complete seal. Do not let the joint get so hot with the torch that the copper fitting turns black.

Right after applying the solder wipe the joint off with a slight damp rag to complete the process. And that’s all there is to joining copper pipe. Good luck with your plumbing project.

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