Lightest possible dome

[Benny D]

I plan to build a 24" pompeii oven that should be as light as possible.

I aim for temperatures around 900 ?F (500 ?C).

Any feedback on the following design of the dome would be much appreciated (described from the inside out):

1st layer: 1" pottery clay, made (and burnt) by a ceramist.
2nd layer: 2" insulation blankets.
3rd layer: 1" concrete

[gugahulk]

Re: Lightest possible dome

This is interesting. Look forward to your build.

[david s]

Re: Lightest possible dome

One inch clay is pretty thin re durability. You will need to use an appropriate clay body. What temperature do you plan to fire it to?
If you are wanting to make it light is there a reason the outer shell is so thick?

[Benny D]

Re: Lightest possible dome

One inch clay is pretty thin re durability. You will need to use an appropriate clay body. What temperature do you plan to fire it to?
If you are wanting to make it light is there a reason the outer shell is so thick?

Thanks a lot for the comment, would you mind to elaborate a little?

1. Durability in what sense? From hit and scratches or heat exposure?

2. What would be an "appropriate clay body"? Shape-wise, it will be a pompeii with neapolitan profile.

3. The pizzas are planned to be fired at 900 ?F / 500 ?C. The clay layer will be burnt twice at traditional temperatures of first 950 ?C and then 1250 ?C.

4. Totally true that the outer layer doesn't need that thickness. As it's only to to protect the oven perhaps I'll go thinner or with some other material.

[david s]

Re: Lightest possible dome

Thanks a lot for the comment, would you mind to elaborate a little?

1. Durability in what sense? From hit and scratches or heat exposure?

2. What would be an "appropriate clay body"? Shape-wise, it will be a pompeii with neapolitan profile.

3. The pizzas are planned to be fired at 900 ?F / 500 ?C. The clay layer will be burnt twice at traditional temperatures of first 950 ?C and then 1250 ?C.

4. Totally true that the outer layer doesn't need that thickness. As it's only to to protect the oven perhaps I'll go thinner or with some other material.

Durability depends on both body composition and temperature fired to.
Generally the higher you fire the body the stronger it will be, but the higher you fire it the less will be its thermal shock capability. Unfired clay(cob) and low fired (<800C) have good thermal shock characteristics. Earthenware and stoneware bodies and temperatures have poor thermal shock, while porcelain bodies and temperatures have good thermal shock. If you want to fire it to 1250 C, you will need a stoneware clay body. Unless you are glazing the dome there is no advantage in firing it twice.
A one inch thick pot will take at least two weeks to dry, maybe more and will need a very slow firing for the first 300 C, and a large kiln to fire it. Personally I think you'd be better off using a castable refractory with stainless steel needles.