How Strong Is a Re-Glued Joint?

If you ever talk to a plumber who has had a glued socket joint pull apart in the field, whether it is above ground or burial, he will tell you that if he can clean up the joint without damaging it, he will re-glue it in place.

Many times the pulled apart joint was not fully seated and the ridge of old glue must be scraped off to allow the new joint to fully seat. The reduction in bond area for the glue to hold is reduced in half if the pipe was only seated half way into the socket. Gaining the safety factor of doubling the bond area usually is enough to make the new joint last.

Sometimes the joint was made with the pipe in so much tension, a coupling and short piece of pipe needs to be added to remove the tension. Many times plumbers will support behind the fitting that came apart with materials that resist the motion that caused the pipe to pull apart.

Realistically, what is the difference between a re-glued joint that failed and a re-glued joint that was forced to fail by debonding it? In the second case, the joint that had not failed is likely to produce a better joint than the one that did fail. Just after debonding a broken piece of pipe from a fitting, the joint surface is in perfect shape to be re-glued because it is clean and warm and it will accept the new primer and new glue better than it did on its first joint.

Surely it is possible to scar the socket wall during extraction and cause other damage to fittings and valves in the process of ungluing it, but Debonding Systems has never heard of a joint that leaked after being re-glued following a proper debonding cycle using a Pipe Debonder tool. We are sure that some day it could happen and we will hear about it, but after 8 years of un-gluing pipe joints, we know of none.

One other point: should there be a lot of the original joint that was never glued or primed properly or if there is a lot of dirt in the original joint, the best way to remove this dirt is to do it right after it is unglued when the socket wall is hot and the glue soft. Besides that, most of the dirt in a glued joint comes out with the pipe, leaving the fitting pretty clean.

There is no ASTM testing data available that we know of for indicating the strength of a re-glued pipe joint.