PEX pipe, a lightweight and flexible alternative to standard copper pipe, is easy to work with, in part because it can be easily connected to many kinds of existing plumbing systems. PEX pipe can be interfaced with CPVC pipe using a conversion fitting that creates a watertight connection between the two.
Make a clean, square cut at the end of the CPVC pipe, perpendicular to its length, using the clamping pipe cutter. If the cut is angled diagonally across the pipe, the connection between the pipe and the fitting will not be watertight. Lightly sand the end of the pipe with the emery paper to remove any burrs or points.
Coat the inside of the plastic-lined side of the PEX-to-CPVC conversion fitting with CPVC cement. Do not use too much cement, or the pipe may become blocked when it dries. Push the CPVC pipe into the fitting until it stops. Let the cement dry completely.
Cut the PEX pipes to the correct length using the clamping pipe cutter, making the cut as square as possible. Lightly sand the end of the PEX pipe with emery paper.
Place a metal crimp ring over the end of the PEX pipe. Squeeze it lightly to hold it in place.
Insert the barbed side of the PEX-to-CPVC conversion fitting into the PEX pipe end. Push the pipe until its end rests tightly against the fitting.
Position the metal crimp ring 1/4-inch from the end of the PEX pipe so it covers the end of the fitting.
Open the the full-circle crimping tool and center its open jaws over the metal crimp ring on the PEX pipe. Squeeze the handles of the tool firmly together, using steady pressure to tighten the ring around the pipe and the fitting.
Measure the crimped PEX ring using the go/no-go gauge, a flat metal template with half-round notches of various sizes that match different sizes of PEX fittings. Choose the notch that matches the PEX pipe size, then slide the notch onto the fitting. If it fits neatly, the ring is correctly crimped and the connection is good. If it does not fit, cut the PEX pipe below the fitting, remove the crimp ring, and reconnect the PEX pipe to the fitting with a new, unused ring.