Building a wood burning oven the insulation

So it's time to insulate the oven. We decided to use fine perlite used to insulate masonry block walls.

First we covered the oven with aluminum foil and framed up the sides using steel studs

Next we covered the front with 1/2 inch Hardie board since the front of the oven will be tiled

The cut out for the door was sealed with fire stop caulk to keep the perlite in

The sides were covered with 1/2 inch exterior plywood using sheet metal screws

   The play wood is 3 feet high to leave room to pour in the perlite. I decided it was cheaper to just fill the entire interior than to install walls in the corners to cut off areas which did not really need to be insulated. The upshot was that we filled the space over the oven with a little over 2.5 cubic yards of perlite. Which gives us an insulation layer of 1-2 feet depending on where you look. We will install plywood the rest of the way up and the final cover on the three sides will be sheet metal.

   For those that like data we fired up the oven to ~400F and cooked a beer can chicken (more on that in a minute) after dinner I cleaned out the oven and put the inner door on. The temp was 350F at that time. Went to bed and got around to checking the oven temp again 12 hours later and it was 326F. So it seems to be losing about 2 degrees per hour in this temperature range. I don't know how that stacks up with other oven builds but I seems pretty good to me.

   As for the chicken, I'll document the next one but here is the bare bones if you will. Brined the chicken in salt water for 5 hours. Grated the zest off of a lime, added olive oil, pepper, and juice of half the lime. Lifted the skin over the breast and thighs and rubbed this mixture under the skin. Smeared the rest over the outside and stuck the remaining 1/2 lime in the neck. opened a can of beer and inserted it into the chest cavity. Stood the chicken up in a cast iron skillet. The beer can and the ends of the legs make a perfect little tripod. slid him in put the inner door on and let it cook for 1 hour 15 minutes. breast temp was 160F. I left the fire in hoping to get some smoke on the chicken but it didn't seem to do much. The meat on the other hand was outstanding. I will refine this and get back to everyone.