How to Connect a Plastic Pipe to a Copper Pipe

What You'll Need
Pipe cutter or hack saw
Emery cloth
Soldering flux
Plastic pipe
Male copper adapter
Female plastic adapter
Propane torch
Teflon tape
Pipe wrench
PVC pipe cement
PVC pipe primer

It is easy to add a plastic pipe to a copper pipe. This may be necessary if your copper pipe has developed a leak. You will need quite a few materials and tools for this project.  Everything you need will be available at your local home improvement store. 

Step 1—Cut the Existing Pipe

Before you begin any type of repair to the water system, you need to turn off the water supply. It is probably easiest to turn off the water supply to the entire house for the duration of the repair. 

Once the water is off, you can cut the copper pipe. You will end up with a cleaner cut if you use a pipe cutter. This tool is found at most home improvement stores. If you don’t have a pipe cutter, however, you can use a hack saw. Make sure to let all of the water drain from the pipe before you move on to the next step.   

Step 2—Prepare the Copper Pipe

You will want to dry the pipe inside and out. Using your emery cloth, you want to sand the copper. The emery cloth will produce a shiny and clean pipe. You should sand the pipe up about 2 inches from the point that you cut the copper pipe. 

You should use the emery cloth on the inside of the male copper component. This will clean and sand the inside of the adapter. 

Step 3—Solder the Copper

With the pipe and adapter cleaned and sanded, you can add the flux to the outside of the pipe and the inside of the adapter. You should cover the entire inside of the adapter with the flux and the pipe should be covered up about 1 inch from the point that you cut the pipe. 

You’ll then place the adapter onto the pipe. You should turn it a couple of times to make sure that flux is covering both the pipe and the adapter.

Turn your torch and apply heat to the area where the adapter and the pipe meet. Once you notice the flux melting and dripping from the pipe, you should go ahead and add the solder to the pipe. The solder should melt and fill into the fitting between the adapter and the pipe. 

Allow the pipe to cool and wrap the threads of the adapter with 4 to 6 layers of Teflon tape. 

Step 4—Prepare the Plastic Pipe

Thread the female plastic adapter onto the male adapter on the copper pipe. You want to turn as far as you can and then use the wrench to tighten it further. 

Once the plastic adapter is on the copper pipe, prime the plastic adapter with the PVC pipe primer. You should also add primer to the outside of the plastic pipe where it will fit into the plastic adapter. Add a layer of cement to the same areas where you added primer. 

Step 5—Connect the Plastic Pipe

Fit the plastic pipe into the plastic adapter and secure it in place while the cement dries and sets a bit. Turn the water back on and check your work.