I've had this idea to make a device to cook pizza in my Weber Performer or Kettle. The idea is to make a frame out of angle iron to hold 8 firebricks. The device will have a 1-1/4" angle iron frame on the bottom with expanded metal spot welded inside. The firebricks will be placed on the expanded metal. A 3/4" angle iron top frame will be slipped over the bottom frame and welded into place. This will trap the firebricks. If my idea works, the bricks will stay in place due to friction of the bricks against each other. The pizza cooker will be approximately 18" x 18" based on firebricks of 4-1/2" x 9" x 1-1/4".
What I don't know is whether or not I can get this hot enough to cook pizza ... sort of like a wood-fired pizza oven. From what I've read, those ovens run around 600° F (but I might have mis-remembered because that sounds awfully hot). I'm thinking that I can put the firebrick frame on top of the cooking grate with a good hot fire. Given a bit of time for the firebricks to heat up, I should get a good hot surface around 400° F to put pizza on. The firebricks should retain their heat well enough that I can remove the lid to place or retrieve pizzas.
Brainstorm or brain f@rt?