So basically, I built this forge out of an old aluminum grill top. My hopes were to use this as a small coal forge for bladesmithing. My question is, will the aluminum shell be able to withstand these temperatures with proper insulation? The shell is approximately 28" wide, 20" long and 8" deep. Essentially, I did a 3 inch layer of pea gravel on the bottom, around a black steel air intake. I used a mound of foundation sand for the pit, and filled in the empty space with a clay top soil. I'm pretty confident that this will be sufficient insulation on the sides/bottom, however I am concerned about the lip of the shell conducting heat. It is slightly raised above the pit and is as close as 8" in parts. I have included a picture of the set up. This is my first forge and I would love some experienced advice. Thanks in advance.