Back Button

How to Join a CPVC Pipe to a Galvanized Metal Water Pipe

Ian Kelly

Because of the escalating price of copper, chlorinated polyvinyl chloride (CPVC) pipe has gained wide acceptance as an alternative to copper tubing in the plumbing industry. However, CPVC in turn is now being replaced by cross-linked polyethylene pipe (PEX) as the leading alternative to copper. To cater to the growing popularity of plastic tubing, the Cash Acme and Probite companies have developed a push-fit connection system for joining any combination of plastic, galvanized and copper pipe together.

Joining CPVC tubing to galvanized pipe without solder or glue is possible.
  1. Thread galvanized pipe with a rented pipe vise and threading pipe die to match the size of the pipe. Clamp the pipe in the pipe vice. Lubricate the end with motor oil and push the threading die over the galvanized pipe. Push in and rotate the die by turning the handles clockwise until you have 3/4-inch of thread on the end of the pipe. Remove the die by turning the handles counterclockwise. Wipe the threads clean.

  2. Wrap a layer of Teflon plumber's tape clockwise around the galvanized pipe. Stretch the tape until it settles into the thread profile. Continue stretching the tape over the threads with spiral turns overlapping half the width of the tape until the threads are covered. Stretch the end until the tape breaks. Smooth the edges of the tape into the threads. Thread a correct size Sharkbite female threaded adapter over the taped thread on the galvanized pipe. Tighten the adapter with a wrench. The other end of the fitting is a fixed tube machined to match the diameter of the CPVC tubing.

  3. Cut the end of the CPVC with a plastic pipe cutter. Make sure that the pipe is cut squarely. Push the CPVC into an appropriate size Sharkbite push-fit connector. Press the pipe inward until you feel the fitting clamp ring inside the connector lock into place. Insert the machined tube of the female threaded adapter into the push-fit connector until it locks into place. This will form a pressure-tight connection between the galvanized pipe and the CPVC tubing.