The most common connection method used in PEX installation is the “Crimp” method. This process involves sliding a ribbed fitting into the PEX tube and crimping a seal ring around the connection point. These rings are typically made of copper, but may be found in plastic as well as brass. The inner edge of the ring is lined with teeth which firmly seal the PEX tube around the fitting. A special sized crimping tool is required for such an installation. All of these materials are very common and can be found at a local hardware supply store.
Another common connection method is a "Cinch" ring. This is very similar to the crimp method in that a metal ring is used to seal the PEX tube against the fitting. However, the cinch ring is considered a cheaper alternative to the crimp method because it eliminates the need for a special sized crimp tool. The resulting seal is as reliable as the crimp method.
If these methods prove to be too complicated for the installer, a much easier connection method is available. The "Press" or "Push" connection eliminates the need for any tools whatsoever. In this method, the PEX tube is simply pushed into a specialized fitting which contains a stainless steel barbed ring. As a result, the ring closes itself around the PEX pipe creating a seal. Although this method is considered to be much easier, the specialized fittings cost more than the standard PEX fittings found in the crimp and cinch connection methods. This method is also viewed as less reliable than standard PEX connection methods because it provides for a larger margin of error.
One final method is a proprietary connection system similar to the crimp and cinch methods. This "Expansion" connection method uses a specialized tool to expand the end of a PEX pipe over brass fitting. Then a metal sleeve is slid over the connection point using another tool until it is snugly secured. Although this method is more expensive to install than a crimp or cinch connection, it is considered to be very reliable.
