Soldier Course & dome angle advice Pompeii Oven Construction Discuss Soldier Course & dome angle advice in the Pizza Oven Design and Installation forums; I've finished laying the oven floor of my 36 inch high vault oven and have the following questions: 1.) I ...

[DimTex]

I've finished laying the oven floor of my 36 inch high vault oven and have the following questions:

1.) I am laying the soldier course with full height bricks set onto the hearth floor. Why should I not mortar the soldier course to the hearth floor? One objective of mortaring the soldier course was to ensure each brick was perfectly perpendicular to the oven floor. Won't the mortar between the bricks flow down to some extent anyway adhering them to the floor in any case. If I don't mortar the brick bottoms should I use the paste to shim the bricks perfectly level?

2.) With a 19 inch high vault a 36 inch diameter and a full height brick as the soldier course isn't there a standard (single) angle I should use for the shims? I say this because in my layout it seems like the last few (3) chains will be close to flat and almost parallel to the oven floor. Does this sound about right?

Thanks

David

[Dino_Pizza]

Hi David, Good questions, here's some answers:

1.) You must not mortar the soldiers on their bottoms. Your dome will expand when hot and it probably will crack if it's mortared on the underside. If our soldiers are on your hearth floor, your floor should only be set with fire clay, sand & water to get it level. The floor expands differently than your dome so you must allow movement. Just be a little more careful in setting your soldiers as perpendicular as possible, and it's ok to be off a bit.

2.) I think it's great thing to achieve a flat top on your last few courses. It's kind of hard to do, but it's great for reflecting heat down, especially for pizza baking. It's actually kinda hard to do in practice, you have to keep fighting the tendency to go up (higher in the dome) instead of curving over to close the dome. At least it was with me.

2.5) If you are putting a full height 9" soldier course on medium diameter oven like yours, you will need to put about a 17 degree angle ( about 1-1/4" down) cut on it so you can start your dome curve, especially if you want to keep at 19" in the center. Maybe others who've done a 36" dome can tell you what they did (mine was a 42").

Keep the questions coming, hope this helps, Dino

[DimTex]

Thanks Dino,

Should I leave a gap between the oven floor and the soldier course? If so, how much? My hearth floor ended up almost perfectly level so there is not much paste required to level things out. When I laid out my oven floor I spent more time brushing away sand/paste to level the bricks than I did having to "fill".

With respect to the 17 degree angle, is that consistent across all the chains or just the first one?

Thanks

[papavino]

People have used a piece of corrugated cardboard between their floor and the soldier course to set the gap width.

[Dino_Pizza]

David, I did what Papvino did (and a lot of others), I placed cardboard box strips around the edge between floor bricks and soldiers and it burns away after a fire or 2. That gives you a little less than 1/4" gap. It may vary a bit because of where your floor brick cuts are as you try to make them "round" with straight cuts on the outer edges. That's ok.

And the 17 deg (make that 16) cut would ONLY be for soldier courses. I've made a drawing and a 16 deg cut works better (1.25" down the front on the soldier brick) The other cuts in my quicky "study" attached here could be all 3 deg cuts. You would have to make minor adjustments as get toward the top rows. Take a look my attached pdf file I just made up. It's just an EXAMPLE of what a 16 deg soldier cut, and 3 deg rings will get you (on paper but it should translate pretty good in real life) for 19" dome height. This is just an example and if anyone sees any problem with it, let me know. I don't want to lead anyone in the wrong directions.

hope this helps, Dino

[bernerdog]

Oh-Oh--I`m on my third ring and worry I may have made a big goof. I`d read that I could (should?) put a thin mortar layer under my soldiers which are 1/2 bricks set upright on top of my floor bricks. Thats what I did, using soft Heatstop. Does Dino`s caution apply if the soldiers are on top of the floor? If so, anything I can do short of tearing up a weeks work?

[Les]

Originally Posted by bernerdog

Oh-Oh--I`m on my third ring and worry I may have made a big goof. I`d read that I could (should?) put a thin mortar layer under my soldiers which are 1/2 bricks set upright on top of my floor bricks. Thats what I did, using soft Heatstop. Does Dino`s caution apply if the soldiers are on top of the floor? If so, anything I can do short of tearing up a weeks work?

You will be fine. If any expansion or shifting occurs, it should simply break the bond and all is good (although heatstop and ref-mix is the equivalent to steel in regard to the brick) It's not like the bricks are going to want to move inches away from where you set them.

Les...

[DimTex]

Dino, All,

Thanks for the info and drawing. Unfortunately I went with your 17 degree number before my computer crashed and I spent the afternoon trying to recover. I guess I can make up the 1 degree difference across the remaining chains.

Which leads me to my next question.... With respect to the soldier course do I spread the paste on the hearth bottom and "butter" the firebrick sides with mortar when setting them or do I set them on the paste and push mortar from the outside into the gap on the back of the joint?

[Les]

Originally Posted by DimTex

Which leads me to my next question.... With respect to the soldier course do I spread the paste on the hearth bottom and "butter" the firebrick sides with mortar when setting them or do I set them on the paste and push mortar from the outside into the gap on the back of the joint?

I believe most will butter the brick on the sides (I did not mortar any brick on the inside, I didn't want to climb in there and clean). You should treat the soldier coarse like all the following courses. In regard to the bottom - I really don't see where it would matter (refer to my previous post). These things end up being quite simple and very forgiving. Keep in mind, we are following a design that is thousands of years old - way before electric brick saws, heatstop/ref-mix, computer programs....

Les...

[bernerdog]

Thanks Les--I`ll soldier on. John