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-   -   Optimal dome thickness? (http://www.fornobravo.com/forum/f9/optimal-dome-thickness-1548.html)

Xabia Jim 02-13-2007 01:25 AM

Optimal dome thickness?
 
The thicker your walls are, the more you approach heat storage designs right? ...or the he more it becomes a bread/roasting oven?

So....How thin can a dome be for a pizza oven? I'm talking fire bricks. What's too thin for a pizza dome?

Also James, I'm curious how small an oven you've found out there. I found a 90 cm one. What's too small?

Thinking about pizza....

Chris 02-13-2007 04:25 PM

Re: Optimal dome thickness?
 
I just finished my dome, haven't fired it yet. It is made of firebricks cut into thirds, for a wall thickness of three inches. I did not parge the dome with mortar.

Hopefully it will cook well. I'll let you know!

dmun 02-13-2007 06:50 PM

Re: Optimal dome thickness?
 
Like chris, I've built, but not yet fired. Mine is bricks laid sideways, for two and a quarter inches. I based my thickness on the thickness of the FB prefab ovens which are two inches thick.

james 02-14-2007 07:27 AM

Re: Optimal dome thickness?
 
This all sounds right. The residential precast ovens range between 2" - 2 1/2" and the commercial ones are between 3"-4", depending on how large they are. The Artigiano is a little over 3". Some precast oven owners coat their oven with 1/2" - 1" extra refractory mortar to build up their mass for heating holding during bread baking and roasting.

My experience is that the basic precast ovens do a very good job of holding heat without the extra mass, and I've spoken with owners who find that if they fire their oven longer, their heat retention keeps going up -- which tells me that they were not completely filling up the mass with heat in their earlier tests. They still had "head room" to build up heat in the precast oven, so they were not using all of the available mass of the oven.

I think the basic theory is that you should completely fill up your available oven mass with heat, and then use high efficiency insulation to stop it. If you haven't completely filled it up, your stored heat will migrate into the outer mass -- away from the inside of the over where you need it for cooking.

Jim, did you see my fancy How Heat Works graphic? Check it out:

http://www.fornobravo.com/forum/f17/...orks-1172.html

James

CanuckJim 02-14-2007 08:28 AM

Re: Optimal dome thickness?
 
James,

I think your "fancy" graphic was posted before I joined FB. It's very helpful indeed and reinforces what I've learned about heat migration through trial and error. Well, done, it's a keeper.

Jim

james 02-14-2007 08:30 AM

Re: Optimal dome thickness?
 
Hey,
That's from someone with an oven that has 12" thick walls. Nice.
James


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