stef
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Posts: 17
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Post by stef on Jun 18, 2018 18:48:12 GMT
Hello all, I am looking for some feedback if that is possible please? I have almost completed my build. I have completed a barrel style oven and have yet to build the front & chimney. See pics. photos.app.goo.gl/GUExi3tT6wg5mZxN9I have fired it a few times now with good results so far. The only issue I note is that it appears to cool down very quickly and that the top of pizzas do not cook completely. I will be adding an arch to the front of the construction which will be lower tha 63% of my dome and will have the chimney on top. My question is this will adding the arch to the front of my build solve my cooling down/not cooking the top of my pizzas issue? See pics here: photos.app.goo.gl/GUExi3tT6wg5mZxN9
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Post by simonh on Jun 18, 2018 20:08:11 GMT
You don’t have anything to retain the heat at the top of your oven and radiate it back out, you can try lifting the pizza with a peel and holding it in the hot airflow for 20-30 seconds at the end to cook the top.
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stef
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Posts: 17
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Post by stef on Jun 18, 2018 20:31:06 GMT
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Post by simonh on Jun 18, 2018 21:19:55 GMT
Looks to be standard bricks though? They are not going to retain the heat as well as firebricks.
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stef
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Posts: 17
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Post by stef on Jun 18, 2018 21:25:24 GMT
The arches are all firebricks, as are the bricks on the oven floor.
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Post by simonh on Jun 18, 2018 21:44:08 GMT
A WFO is a thermal sink, you are using fire to put heat into the mass of the oven and then using the slow release of that heat to do your cooking for you. The interior of the oven needs to store and release that heat slowly over time. The best way to do this is to use materials that do this well such as firebricks.
The next step is to try and keep all of that heat where you want it most so insulation is key, under the floor is really important but over the top and the rear wall need as much as you can put in. A front arch and a chimney will also help as you can slow down the airflow and stop heat escaping that way.
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Post by chas on Jun 19, 2018 7:50:45 GMT
As ever, it depends. eg you don’t need much insulation to cook one pizza. A bit of insulation particularly in the floor helps smooth out the process of cooking several pizzas, You need insulation to cook a slow roast and it will help with pizzas too. Full insulation and a relatively low temperature will cook a pizza dough through nicely and bake toppings too - but a high temerature will just burn the outside of the dough and the toppings leaving much raw. A thin base with just a smear of tomato paste will cook nicely in a hot oven. So what insulation gives you is a degree of controllability. What is generally agreed is that the arch, and its ratio to the hight of the dome is key to retaining some heat - think of it as a sort of dam - to get the flame rolling across and over your pizza without immediatly escaping up the chimney or out the door. The materials used are less important as long as you compensate. Chas
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stef
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Posts: 17
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Post by stef on Jun 19, 2018 8:36:09 GMT
Fantastic advice, thanks!
I’ve established that the oven floor is 40mm too low if I want to attain the 63% gold standard and that I need the arch at the front.
So my plan now is to build the front arch (today) and then reassess to see if it improves. I may add a 40mm layer of vermicrete on top of the existing 100mm one to lift the oven floor but I’ll see how much an effect adding the front has first.
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stef
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Posts: 17
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Post by stef on Jun 20, 2018 19:21:50 GMT
Front arch added. You can’t see but there is a 30mm x 200mm slot chimney behind this and in front of the existing structure. The flue will be built in the next week or so . photos.app.goo.gl/KwWNkPxD2hL8T6eD9
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Post by downunderdave on Jun 20, 2018 20:43:16 GMT
Front arch added. You can’t see but there is a 30mm x 200mm slot chimney behind this and in front of the existing structure. The flue will be built in the next week or so . photos.app.goo.gl/KwWNkPxD2hL8T6eD9That sounds way too small. You don’t say what size your oven is, but as a guide a 600 mm diam hemispherical oven requires a 150 mm diam flue or equivalent cross sectional area and a 1000 mm oven a 150 mm flue.
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stef
member
Posts: 17
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Post by stef on Jun 21, 2018 11:15:16 GMT
OK, thanks. I’m going to have to go with it as I’m pushed for space on the footprint. I know that some ovens don’t have a flue at all so I’m sure hat it will work but it may not be the most efficient. Let’s see. It’s gettin a firing on Sunday so we won’t have to wait long.
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