Island Hearth

[masuzzu]

I am thinking of building an ISLAND HEARTH as described in the Pompei Oven Instructions.
1) Can I use clay splits (1 1/4" clay bricks) instead of firebrick splits as described in the Instructions?
2)What happens if I use the whole brick instead of the split brick?
3)Will the ISLAND HEARTH effect the initial heat up time for pizza's?
4)The instructions call for REFRACTORY CONCRETE and INSULATING CONCRETE.Are they one and the same?

[dmun]

Originally Posted by masuzzu

I am thinking of building an ISLAND HEARTH as described in the Pompei Oven Instructions.

Is this still in the instructions? It was a transition between the discredited insulation layer below the support slab method, and our current cooking floor directly on the insulation method. Additional mass below the cooking floor is not needed for pizza: only consider it if you need additional thermal mass for repeat loads of bread or other retained heat baking.

1) Can I use clay splits (1 1/4" clay bricks) instead of firebrick splits as described in the Instructions?

No reason why not. Once you get beyond direct contact with fire, mass is mass.

2)What happens if I use the whole brick instead of the split brick?

Even more mass = Even more time and fuel to heat up.

3)Will the ISLAND HEARTH effect the initial heat up time for pizza's?

Absolutely yes.

4)The instructions call for REFRACTORY CONCRETE and INSULATING CONCRETE.Are they one and the same?

No. Refractory concrete, often referred to a castable, is a special non-portland refractory concrete that will withstand exposure to high heat. It is solid, and behaves like firebrick. There are a lot of different brands and blends, and some of them need to be cured at high heat to be effective.

Insulating concrete can be as simple as vermiculite (or perlite) and portland mix, or a specialty refractory product. They are meant for insulation, not direct contact to high heat of flame.

[asudavew]

Originally Posted by masuzzu

1) Can I use clay splits (1 1/4" clay bricks) instead of firebrick splits as described in the Instructions?

Yes, but eventually the clay brick will start to spall.. meaning they will start to break up and drop pieces of brick into your oven and food. (Best to stick with firebricks. The extra expense is small compared to the total cost of the build.)

Originally Posted by masuzzu

2)What happens if I use the whole brick instead of the split brick?

I'm not sure if I get you here... but if you are talking about using whole bricks to build the dome....... it's hard enough to get a nice dome with half bricks. And by the time you reach the top you will probably be using thirds. I don't think whole bricks would work.

Originally Posted by masuzzu

3)Will the ISLAND HEARTH effect the initial heat up time for pizza's?

It shouldn't, because on top of the cinder block base, you will pour a 3 1/2 inch layer of reinforced concrete - this is the hearth slab.
On top of that you will pour about a 4 inch slab of insulating concrete (5 parts vermiculite or perlite mixed with 1 part cement -NOT QUICKRETE but portland cement.)

Originally Posted by masuzzu

4)The instructions call for REFRACTORY CONCRETE and INSULATING CONCRETE.Are they one and the same?

No they are not the same.
Refractory MORTAR is used for the brickwork. Insulating concrete is used over the hearth slab, and you will place your hearth bricks on top of it.
Then when the oven is complete, more insulation over the dome.

Remember - Insulate, Insulate, Insulate.


I hope this clears things up a bit for you.

Dave