Jeremy5848's recommendation is a good one. I lived with one leaking for two years. Had some success wrapping fine wire into the crack. Other methods used were muffler cement, epoxy, exhaust wrap tape.
Thought about high temp (600-800 degrees) silicone hose, slit down side hose clamped into place.
Replaced joint when head gasket was done. Found a back exhaust stud broken.