How to Cut and Crimp PEX Tubing Like a Pro

Before beginning any work, gather all the necessary tools and materials in your workspace. This includes your roll of PEX tubing, the appropriate PEX crimp fittings (e.g., couplings, elbows, tees), and a supply of copper crimp rings matching the tubing diameter. Your essential tools will be a dedicated PEX tubing cutter, a PEX crimping tool calibrated for your ring size, its corresponding go/no-go gauge, and safety glasses for eye protection. Laying everything out ensures an efficient workflow and prevents interruptions.

Measure the desired length of your PEX tubing and make a clear mark. Place the PEX tubing cutter on the mark, ensuring it is perpendicular to the pipe. Squeeze the handles of the cutter firmly to slice through the tubing. A proper PEX tubing cutter is designed to make a perfectly square and clean cut. Avoid using hacksaws, utility knives, or shears, as they can create burrs, deform the tubing, or result in an angled cut, all of which compromise the seal and can lead to future leaks.

Take one copper crimp ring that matches the diameter of your PEX tubing. Inspect the ring to ensure it is perfectly round and free of any dents or damage. Slide the crimp ring over the freshly cut end of the PEX tubing. The ring should slide on easily and move freely along the pipe.

Select the correct PEX crimp fitting for your connection. Hold the PEX tubing firmly and push the barbed end of the fitting straight into the opening. Apply firm, steady pressure to insert the fitting until the PEX tubing makes contact with the shoulder or base of the fitting. You must ensure the tubing is pushed all the way on; any gap between the tubing's end and the fitting's shoulder will result in a failed connection.

Slide the copper crimp ring down the tubing until it is positioned over the barbed section of the fitting. The correct placement is critical: the edge of the ring should be between 1/8-inch and 1/4-inch from the end of the PEX tubing. Do not let the ring touch the fitting's shoulder. Open the jaws of the PEX crimping tool and place them squarely over the ring, ensuring the tool is perpendicular to the pipe. Squeeze the handles of the crimper completely until the tool's mechanism fully closes and bottoms out. You will feel a distinct stop. Release the handles to remove the tool.

This is the final and most important quality control step. Take your go/no-go gauge. First, attempt to slide the 'Go' slot over the compressed ring. It should fit snugly. Next, attempt to slide the 'No-Go' slot over the ring. It should NOT fit. If the 'Go' slot does not fit, the ring is under-crimped. If the 'No-Go' slot fits, the ring is over-crimped. In either case of failure, the connection is bad and must be redone. Use a special ring-cutting tool or carefully cut the ring off with a rotary tool, remove the fitting, and start over from Step 2 with a new piece of tubing, a new ring, and a new fitting.