New Mexico Pipe Fitter Journeyman (JPF) Practice Exam

What is one common method to remove a pipe that will not unscrew from a cast iron fitting?

1. Use a pipe cutter

2. Heat the joint

3. Hit the fitting with a hammer

4. Apply lubrication

The correct answer is: Hit the fitting with a hammer

When dealing with a stuck pipe that will not unscrew from a cast iron fitting, one common method is to apply heat to the joint. Heating the fitting causes it to expand, which can help break the bond between the pipe and the fitting. This thermal expansion can make it easier to unscrew the pipe, as it allows for the potential separation of rust or corrosion that might be holding the two parts together. Using a pipe cutter is more suited for cutting through the pipe itself rather than freeing it from the fitting. While lubrication may assist some threaded connections, it is less effective with corroded or rusted joints typical of cast iron fittings. Hitting the fitting with a hammer carries the risk of damaging the fitting or creating micro-cracks in the cast iron, which can lead to leaks or further complications in the plumbing system. Therefore, applying heat stands out as a reliable and commonly accepted method for this specific issue.