First time oven builder

[Rob Legg]

Hi - I'm building a largish w.f.o. ID 1200mm (48") and now is the time for all good men to come to the aid of the party! I've read the FornoBravo (F.B.) info on their largest 42" Tuscan/Naples and have the following questions:-
1. first dumb question - What exactly is thermal mass? As applicable to w.f.o. i.e. F.B. say "too much thermal mass is bad".
2. The only fire bricks I can access are high and medium duty. Med duty alumina (AL2O3) 32% silica (SLO2) 52%. Thoughts on that....? Do the boys at F.B. answer queries?
3. 2nd dumb question - I read on the F.B. forum that the ideal ratio between opening height and roof height is 63%. Does this apply to me?
4. The oven is for commercial use and the emphasis will be on bread and food dishes. Pizzas as as well. The happy medium would be good Tuscan/Naples so suggestions on roof height would be most welcome.
5. F.B. says that putting a bed of fire bricks under your cooking surface for the bread baking area enhances the baking. Anybody with experience in this area?
6. Med duty bricks at the current rate of exchange are $1.85 each. Does this set a record?
Any help would be much appreciated.
Rob from South Africa

[dmun]

What exactly is thermal mass? As applicable to w.f.o. i.e. F.B. say "too much thermal mass is bad".

This is the amount of heavy, refractory masonry that heats up and reflects the heat back for cooking purposes. As opposed to, say, the insulation that surrounds it. "Too much thermal mass is bad?" Remember, most of us are backyard pizza cooks, who what to heat an oven up quickly with minimal fuel to cook a few pizzas for dinner. Thermal mass isn't necessarily bad if you have a commercial oven that's fired every day, which never really cools down.

The only fire bricks I can access are high and medium duty. Med duty alumina (AL2O3) 32% silica (SLO2) 52%. Thoughts on that....? Do the boys at F.B. answer queries?

Medium duty bricks are fine. A little harder to cut, but they will bake just as well. And some of the forum's most active members are female

suggestions on roof height

Hemispherical is easy and strong. Low domes may need buttressing because of side stress. These are more typical of Naples.

Med duty bricks at the current rate of exchange are $1.85 each. Does this set a record?

Builders in Australia and the UK are paying almost twice that.

[Les]

Originally Posted by dmun

Remember, most of us are backyard pizza cooks, who what to heat an oven up quickly with minimal fuel to cook a few pizzas for dinner

I am discovering, that with good insulation, you can build an oven using the FB plans and cook for day's. I can bring mine up to heat using 7 moderate pieces of oak. Like David said, if you are commercial, you may want more mass. For your home - these things are awesome!

Les...

[gjbingham]

If you're seriously considering the majority of your use to be for bread or foods that will cook at 650 degrees or less, you might consider a barrel vault style oven. Perhaps a quick research of books like "The Bread Builders" will give you additional information for your consideration. You'd be hard pressed to get this style oven to 850 degrees for a true Neopolitan pizza, but you can bake a (lower quality by all accounts) but yummy pizza none-the-less, and and do a heck of a lot of bread and other baking.

These pizza oven plans described on this site are intended to heat up quickly and get really really hot. They will not typically maintain heat for multiple bread bakes without refiring. They are pizza ovens that can be used to bake a load of bread and/or other foods. You need to consider/decide what the primary purpose of your oven is, then build the style of oven appropriate for your intended purpose. That should help you decide on your direction.