Encyclopedia & FAQ's

DIY Frequently Asked Questions / Coupling


  • DIY Frequently Asked Questions / Coupling')"> Connects two lengths of pipe.
  • Has female thread on both ends (for galvanized pipe) or no threads (for copper, PVC and other solvent-welded pipe).
  • A Reducer Coupling joins two different sizes of pipe.
  • An Adapter Coupling joins two different types of connection types, such as threaded and solvent weld.
  • A Repair Coupling, or mender coupling, has no center stop so two lengths of pipe can be fastened together. Use on unthreaded lengths of pipe.
  • A Fitting Trap Adapter adapts PVC to tubular traps used for sinks.