Dome height vs Stability

[fourlambs]

Hello all,
I have just completed my 'soldier course' on top of my base and now need info on dome height (I have browsed for info but am confused...), I also understand that a dome too low can have an impact on structural stability...?

The facts;
My internal floor diameter is 97cm.
The angle cut on top of the soldier course is 20 degrees
The door internal height when complete will be 31cm, internal width 64cm

So how high does the dome need to be?

The oven will cook mainly pizza and breads....

I have link to images, you will see my approach may be a little different but this is due to circumstances.....

Library Slideshow by Fourlambs | Photobucket

All advice appreciated, thanks Phil

[brickie in oz]

Re: Dome height vs Stability

Welcome Phil.

My biggest concern is that it looks like you have no under hearth insulation?
Is that right?

You also have concrete piled up underneath the soldiers, you will need a forest of fire wood and heaps of time to get the thing hot.

[Laurentius]

Re: Dome height vs Stability

Hi Four,

Before you sacrifice the lambs, tear that baby down. Don't hesitate, insulate. Al is right, and you are at the ideal stage to correct your wrong.

[david s]

Re: Dome height vs Stability

Hello all,
I have just completed my 'soldier course' on top of my base and now need info on dome height (I have browsed for info but am confused...), I also understand that a dome too low can have an impact on structural stability...?

The facts;
My internal floor diameter is 97cm.
The angle cut on top of the soldier course is 20 degrees
The door internal height when complete will be 31cm, internal width 64cm

So how high does the dome need to be?

The oven will cook mainly pizza and breads....

I have link to images, you will see my approach may be a little different but this is due to circumstances.....

Library Slideshow by Fourlambs | Photobucket

All advice appreciated, thanks Phil

A hemispherical dome for your oven would have a height of 48.5 cm. 63% of this gives you 30.55cm If you want a low dome height then your door should be 63% or thereabouts of the internal dome height.

[fourlambs]

Re: Dome height vs Stability

Thanks all,

.... but I can confirm that there is full square meter of calcium silicate under those tiles and a good solid concrete foundation, around 20cm thick, under that.

Does this satisfy the doubters???


David S, 48cm is roughly where I was thinking, so thanks for the confirmation.

Phil
Dandenong Ranges

[brickie in oz]

Re: Dome height vs Stability

Does this satisfy the doubters???

Not doubters, there has been sooo many builds on here where the builder has omitted the insulation, then the cant work out why the oven wont get hot?

We are here to offer help, sometimes its just too late for it.

[mrchipster]

Re: Dome height vs Stability

Thanks all,

.... but I can confirm that there is full square meter of calcium silicate under those tiles and a good solid concrete foundation, around 20cm thick, under that.

Does this satisfy the doubters???


David S, 48cm is roughly where I was thinking, so thanks for the confirmation.

Phil
Dandenong Ranges

It sure looks to me like the ceramic board is only under your floor tiles and not under the soldiers. Heat will wick out of the walls also and cause the oven to not heat properly

[fourlambs]

Re: Dome height vs Stability

Ok, after much toiling and learning along the way, the dome is complete. I am rather proud of how the top ended up, as I was worried there for a while!

image_zps43785169.jpg Photo by Fourlambs | Photobucket

I am now contemplating the finish and I am considering the perlite / mortar mix over the blanket, but also wondering what other finishes I could use? Also, at what point does this become water tight?

Cheers
Phil

[Greenman]

Re: Dome height vs Stability

Hey Phil - It is good when the keystone goes in and it starts to look like the real deal. I put 2 layers of blanket followed by 2"of vermicrete and render over the top of that. I finished the whole deal with Dulux AcraTex to seal it.

It isn't really waterproof until the acrylic sealer (or whatever you chose to use) goes on as the render will still absorb moisture.
It also pays to have a vent to allow any moisture trapped in the layers to escape when you fire it up. Mine is a poly fitting with a capped thread and the little chinaman hat on top is just my idea of decoration.

Plenty to do before the smell of cooked food comes out of the dome but you are well on the way. Congratulations.