The chances of collecting a puddle of cement, along with the reduction in wall thickness adjacent to the pipe stop, are by far more responsible for joint failures than shorter socket lengths. Since the fitting socket has a slight taper, a pipe that is not seated to the stop can have a gap between it and the fitting, which has to be filled with enough solvent cement to prevent a leak.
Every brand and every formulation of solvent cement contains PVC, which is left to fill any gaps and voids when the solvents evaporate. That residual PVC is not of the same density as either the pipe or fitting material and it is not as strong. This will result in a joint that is much weaker than one with a tight fit that allows the pipe and fitting materials to fuse as one.
Our analysis of many joints returned from the field over the years clearly illustrates that the most common cause of solvent joint failure is the lack of cement or improper application, not socket depth. Although making a good solvent cemented joint is very basic, there are a few points that need to be emphasized.
The first step is to remove all burrs and rough edges from the end of the pipe. Then, using an applicator at least one-half the diameter of the pipe, apply primer to both the pipe and fitting socket. Immediately, again with an applicator that is half the diameter of the pipe, apply a coat of cement to the pipe end. Apply a light coat of cement to the fitting socket. Add a second coating to the pipe. Assemble both parts with a twisting Circle 139 on Reader Response Card motion. Finally, allow sufficient time for the joint to cure before moving or applying pressure. If you follow this procedure, you can rest assured the joints will not leak and the socket depth is no longer a concern.