If you are talking about mounting a Gen-Turi.. Then this may help you.
You would think that with the hot exhaust gasses that pipe would get hot, very hot, however only one time has mine gotten hot enough to be uncomfortable (NOTE, DO NOT TOUCH THE METAL PARTS WHEN THE GENERATOR IS (or recently has been) running, ONLY THE BLACK PIPE.
I can, if I must, open the door, start the generator, (or service it) then pop the extension on (It just slips in and pins) then when I go to shut down use PLIARS to pull the pin (Which is now lost anyway) and remove the unit without touching the metal or only touching it with heavy leather (the edge of the sole of my shoe)
The one time It got too hot to handle.. it was the SUN, not the generator, that made it that way.