:ahhh: CAN ANY ONE PLEASE HELP ME ? I HAVE A NEW HARMAN TL WOOD STOVE THE PIPE IS 6" AND THE CLAY IS 7" THE SALESMAN SAID TO STUFF FIBERGLASS INSULATION TO TAKE UP THE DIFF. I WAS THINKING OF DOUBLE WALL 6" .WHAT IS THE CORRECT WAY? NO COMBUSTABLES TO BE CONCERNED WITH BUT WHAT IS THE BEST SOLUTION? THANKS, HOT PIPE.