A copper pipe crimp holds when the tube is cut square, deburred, fully seated, and pressed once — then checked with a go/no-go gauge.
For the full breakdown, see our best Copper Pipe Crimping Tool guide.
One angled cut, or a second squeeze of the handles, can turn a finished joint into a leak that only shows up a month after the water is back on. Crimping copper — pressing a fitting or ring onto a prepared tube with a matched tool — takes seconds and holds for decades when the tube is prepped correctly and the tool closes once, fully, and square. The nine steps below cover how to use a copper pipe crimping tool from measurement through the final gauge test, plus the seven mistakes behind most failed joints.
Using A Copper Pipe Crimping Tool: Nine Steps, In Order
Every connection follows the same order: prepare the tube, seat it fully, press once, and prove it with a gauge. Cutting corners on the prep or repeating the squeeze is what kills joints.
- Measure and mark the length. Dry-fit the run before you cut so the mark lands where the fitting seats instead of past it.
- Cut the tube square with a pipe cutter. Manufacturer instructions warn against a hacksaw here. A jagged or angled edge sets the joint up to fail before anything is pressed.
- Deburr the inside and outside edges. A burr can nick the sealing element or O-ring as the tube slides into the fitting, and that nick is where