I am making a small, inexpensive pit for direct heat charcoal grilling. My son passed through Memphis and fell in love with Rendezvous ribs, so we are looking to cook at 350 18" over the coals (we will start at 18", but the height is adjustable to find the perfect distance for holding 350 at the grill on this contraption). I got an old New Braunfels Red River charcoal grill and separated the ash pan from the lid. The ash pan goes on bricks inside the cinder block sides that the lid sits on. The sides go up against my fireplace chimney which provides the back. All I need is a door or doors for the front. Being on a tight budget, I want to use a piece of 3/4" plywood I have for the doors and simply line it with whatever tin or thin sheet metal I can scrounge. As long as I line it with metal, I am thinking that the plywood will be protected from the flames and should never pose a fire threat. What do you all think? Anybody have experience with this sort of thing? Thanks!