Hello, I am getting some chimneys repaired. When knocking in the quoins, the masons broke a 4" square section off an adjacent facing stone (sandstone). This left a hole in the chimney. He wants to glue the broken piece back in with 2 part epoxy. The alternative is to take down the chimney and rebuild. Any thoughts or experience in this method of repair? The mason comes with a good reputation working on many historic buildings.