Day 11 - The Cladding

If you are building an oven, you will notice as you go along that there will be times when you have to say to yourself "I wish I did it differently." I had a few of these moments today, but in the end, everything seems just right. The first thing is that I wish I made my hearth slab wider in order to give me thicker side walls. My side cladding is only 2.25 inches at the widest part, and only about an inch on the sides of the firebrick. It would have been great if my side cladding was 3 inches. As I put the reinforcing wire, the plans call for two layers, and with such thin walls, this seemed unreasonable. So the sides of my oven unfortunately just have one layer of reinforcing wire. The second thing I would have changed was that when I did the corners (right after putting in the arches), I would have used pieces of brick cut more precisely to make a smooth arch-like feel. These corners really give you a hard time when dealing with reinforcing wire and aluminum foil. And the third and more simple thing I would have done differently was to lay one more course of chimney brick so that my cladding could come higher in the front (but we found a solution to that, which you will see below).

So the first thing we did was wrap the oven in heavy duty aluminum foil. I originally thought that the purpose of this was to reflect heat back into the oven, but I was mistaken. The main purpose is to create some "slippage" so that when the bricks expand, it is not "glued" to the cladding. This way, both layers can expand and contract somewhat independently. After wrapping it with foil, I shaped the 6x6 reinforcing wire to end up in the middle of the poured cladding. My plan is 2.25 inches on the sides (wish it was 3), and 5 inches on the top. I put two layers of wire on the top (with bigger walls, I would have definitely put 2 layers on the sides as well). This process was painstakingly slow as I was trying to get the shape just perfect and ended up taking me a couple hours.

I kept a light in the oven prior to pouring in order to add some heat to the oven. This puts the bricks as somewhat of an expanded state at the time of the pour. This may help in preventing more serious cracking of the cladding (which is bound to happen after your first serious firing, but that is what the reinforcing wire is for).

All ready for the pour.

This was our solution to not adding another course to the chimney - just put in temporary bricks for the pour, and take them out once it has set some.

Put plastic and then a canopy over it to slow the curing process.

This was a little disaster that ended up being no big deal. Our corner busted open when the brick wedge at the bottom slipped out. We didn't want the concrete filling in the air gap between the hearth slab and the block wall, so I slipped some boards in there to prevent it from doing so. All this really did however was give me a thicker wall at the corner - just what I wanted right?

When the corner busted out, we tapped the walls to get the concrete settled a little too gingerly - leaving these air gaps. No big deal though, we just filled them with a sand/cement mixture.

Now we let it cure for a couple of weeks. Then pizza time!