Day 6 - The Walls

Like I have already said, before cementing in any of the walls, make sure you know exactly where you want any of the bricks. This is my last and final mock-up. After it all is set up, I marked each brick with a pencil, even down on the sides of the firebrick as well where each brick should lay. The most crucial bricks are the door jam bricks. See below.

This mock-up is even a slight modification to the previous one. I set back the
door jam bricks to more easily tie into the facade without having to cut bricks.

Carefully mark where the bricks will go

The mortar used for this project is a very strong and fast-setting mortar (10 parts sand : 3 parts cement : 1.5 parts fireclay). To say the least, this was a very frustrating endeavor for me, but with a little practice, I became better at it by the end. Especially if using portland, it really sets up fast once it touches a brick. Also, the more you tamper with it, the harder it will get. At times, it seemed to set after 15 seconds of fiddling with tapping the brick so it is in just the right position, leveled to itself and to the surrounding bricks. This did not give me enough time to get it just perfectly in place and I would have to take the brick out, and throw away the mortar because it has already become set and immaleable. So from all my frustrations, I feel like I can give a few pointers. Don't neatly tamp the mortar before you place the brick on it... just slap it on there as loosely as possible and let the brick smash itself into position, but get it to the correct mortar joints quickly, always keeping the level and rubber hammer handy. And it doesn't just matter how fast you get it into position, it matters how many times you tap it - the more you tap it, the faster it will set - so no unnecessary baby taps - it will go solid before it is in position and you will have to take it out and start with fresh mortar. Also, I dunked the bricks in water for a few seconds and let them drip dry a few minutes before using them - this helped a lot.

The four pictures below have different ways I dealt with the big mortar joints at the corners. The first three of these I did, I just filled it in with a lot of mortar. All of these ended up with fairly large vertical cracks, and one of them actually lost its bond to its neighbor and I had to redo it. So for the last 6 of these joints, I filled them in with angled brick pieces and these ones did not crack because they has more or less normal mortar joints.

One large solid mortar joint. Notice the crack on the right.

I filled this one in the brick pieces and it worked a lot better.

You cannot tell that the big joint on the right has brick pieces in it, but it does.

I took the bottom supports out. Fortunately it held its own just as expected! 

Progress to date 

So next is pouring some cladding about 3/4 up the wall so the arches do not push them outwards. But before we start on the arches, We need to lay the facade brick on the bottom half of the oven because our granite slab will rest on this brickwork, and I need to lay some brick on this granite slab before I lay any of the arch bricks. So next day of work will be collecting some more free bricks and laying up the walls to hearth level.