t's not a surprise to anyone that PVC plumbing pipe and fittings are easier to install and repair than cast-iron versions.  In areas where local codes allow you to convert from cast to PVC, it's almost always worth the time to make the change. Fortunately this job is pretty easy because schedule 40 PVC pipe is very close to the same size as cast iron in all the standard wast-pipe sizes. So you can use standard neoprene gaskets in the cast hubs to hold PVC pipe. Be sure to clean out the hub, and remove any metal burrs installing the gasket.

    1. Press a standard-sized neoprene gasket into the hub, and push it until the gasket lip is flush with the hub lip. If the gasket doesn't sit flat, remove it and clean out any debris that is preventing the gasket from seating completely.

    2. Once the gasket is seated, spread liquid dish soap on the top and inside of the gasket to act as a lubricant(insert). Then cut the PVC pipe to length, and remove any plastic burrs from the inside and outside of the pipe with a file.

    3. Place the de-burred end of the pipe against the top of the gasket, and drive it into the fitting until you feel and/or hear the pipe hitting the bottom of the hub. Hold the pipe securely when you strike it.