I watched someone seal a leaking 3" dwv pipe connection in a simple way. But I wonder if it is only a temporary fix that will not last long.
He first put purple primer around the rim of the connection that was leaking. He said "the primer helps the glue penetrate".
After the primer dried, he put PVC glue around the rim of the leaking connection. This method sealed leaks around the rim of a w/c flange, a 3x3x2 wye, and a 3" quarter bend.
The next time we filled the dwv with water there were no leaks. Will this fix last?