Fire: Too Hot - Too Cold

[shuboyje]

Re: Fire: Too Hot - Too Cold

Sadly I see a lot of reasons why you are having issues. A 23" high dome on a 30" oven is way to high. Even a full hemispherical dome would only be 15". The next issue is the opening size. An 18" wide opening in a 30" oven is pretty big, and you are gonna lose a lot of heat. Last issue is the 2" of sand and 2" of insulation. Sand adds to the thermal mass, and if you already have fairly thick bricks the result would be a very massive oven. Also depending on the type of insulation, 2" is not much. If it is a blanket you may be able to slip by with two inches but if it is vermiculite or perlite you would need at least double that, and triple would even be a good idea. So now to sum it all up: A oven with extra mass to heat up, a very high dome, and very large door, and a lack of insulation probably will not get up to pizza temperatures. You also didn't mention if it is insulated under the floor?

[louise]

Re: Fire: Too Hot - Too Cold

hi many thanks for your reply i think ill take some photos and post them to you. Im not sure exactually how it is insulated. He is a stone mason and knows a lot of stone but not about mainting the heat. He spent a long time getting it right. I will get him to write down exactually how he did it and how insulated and i will get back to you. I really appricate this help.

[Spunkoid]

Re: Fire: Too Hot - Too Cold

Louise,
I agree with Shuboyje in that it is a pretty large opening and quite high but with good fire management, you should still be able to get it hot enough to cook a few pizzas.

Suggest starting your fire small then building it up hot, really hot. Use dry wood, split it lots, keep feeding the fire and keep it pushed well back into the dome and to the side. Build up a good heavy bank of coals. When the dome is cold, it will likely get black with soot. When it gets really hot, the soot will burn off and you will be able to see the bricks well. Spread the banked coals all around the edge of the dome and add a few sticks of wood to the one side. The flames should slowly lick over the roof of the dome on the inside and lazily come down the other side. You should find it more than hot enough to cook a pizza or two.

On the plus side, with the large opening, and the higher roof, it can be corrected if need be by cutting and adding another layer of fire brick to the floor, you have more than enough room to do it, it just won't be easy.

[louise]

Re: Fire: Too Hot - Too Cold

God im amazed at the response i am very greatful. I discussed this with him yesterday and he was concerned about lighting a bug fire as he is worried about the brick. I advised him to make the fire larger and hotter. We are hoping this may work. We are both new to pizza ovens especially hand built brick one's. We will be lighting a bigger fire with more heat on saturday fingers crossed we will get it hot enough to cook a pizza. I will take pictures and post them over the weekend. One again many thanks for all your help. No doubt we will talk soon.


Louise

[GianniFocaccia]

Re: Fire: Too Hot - Too Cold

Louise,

I believe another builder here had the same concerns with an opening arch that was too high. Depending on how yours was built, you may be able to build a small arch 'insert' that would effectively lower the entry height. As Spunkoid suggested, if 2 1/2" is added to your floor, your dome height would be 20 1/2". Adding 2 1/2" of arch to the entry would bring you to the ideal dome/opening ratio of 63%. Pics would be helpful.