Dome Size

[Luxy]

Hello, I am quite new to the site and to building a wood fired oven but I sure do like what I am seeing and reading here. My question though is about dome height. From what I have read it is ROUGHLY half the diameter of your width in a round oven. Now my plans are to build a smaller oven aound the 28in mark. That would make my dome 14in tall and if you use roughly 61% of that height for your entrance, that gives you an 8.5in opening. I would like to be able to do something like a beer can chicken in it so that opening would be a little small. Next i noticed that the Primavera70 28in oven has an external dome height of 26in. So if you take 2in off for the cast cement and 3in off for insulation, that gives you a dome of 21. Do they make the dome higher to get a bigger opening? Would their be any draw backs to doing this?

Thank you

[Lburou]

Originally Posted by Luxy

Hello, I am quite new to the site and to building a wood fired oven but I sure do like what I am seeing and reading here. My question though is about dome height. From what I have read it is ROUGHLY half the diameter of your width in a round oven. Now my plans are to build a smaller oven aound the 28in mark. That would make my dome 14in tall and if you use roughly 61% of that height for your entrance, that gives you an 8.5in opening. I would like to be able to do something like a beer can chicken in it so that opening would be a little small. Next i noticed that the Primavera70 28in oven has an external dome height of 26in. So if you take 2in off for the cast cement and 3in off for insulation, that gives you a dome of 21. Do they make the dome higher to get a bigger opening? Would their be any draw backs to doing this?

Thank you

You seem to have read some of the same information that we have seen, and you seem to have a grasp of the basics you cite. There is wiggle room in all the numbers. How much wiggle room? Nobody really knows....I think there is more wisdom than wiggle room there

I plan to make our dome height about two inches taller than the radius of my dome, allowing for a taller doorway and still abiding by the 63% door/dome height ratio, then, living with a narrower doorway than one could build.

I asked about the advisability of a higher dome and such a departure from the plans in open forum, but got no feedback, positive or negative. I'm willing to take the risk, I think its a small risk.

[GianniFocaccia]

FWIW, I think a 28" oven may be a little small. The smaller door size makes it more difficult to see as well as manage your fire and food. More importantly, remember that even a gentle fire on one side of the oven reduces your usable cooking floor space, which may tend to provide a smallish 'cooking zone' that isn't too hot to scorch what you're cooking. Of course, if your space is limited, go for it.

[Luxy]

I agree that 28in is on the small side but unfortunately until our 80 acres of land is finished re-zoning we are stuck in the city with our small lot. I figure I will build and learn from the smaller one and when we do move, I will know what not to do.

Lburou, what size are you planning? And you are going to increase the dome height by 2in?

[stoveup]

Luxy, if you have the space, keep in mind that there are several advantages to a larger oven. For one, when a WFO is heated it does not heat perfectly evenly. The variation in temperature across the hearth is especially large with the outside edges close to the dome being hottest. The sweet spot is an area around the center of the hearth that is relatively even in temperature. The smaller your oven, the smaller the sweet spot will be.

Cooking a pizza close to the dome requires almost frequent turning of the pizza while it is cooking to avoid overcooking the side closest to the dome wall. On the other hand, cooking a pizza in the sweet spot closer to the center of the hearth (and not too close to the fire) will require less active handling of the pizza during cooking.

Mklingles has done some preliminary modeling of heat distribution across the hearth HERE (Mathematical analysis of dome geometry). Take a look at the first two images in post #1 which compare heat distribution across the hearth for differences in dome height. They clearly illustrate the relative eveness of temperature across the hearth until you get close to the outside edge where the heat intensity doubles. Be sure to read mklingles comments immediately after the second image.

God bless the obsessive-compulsive engineers on this forum! There is so much I would never learn without them!

[Luxy]

Stoveup, I can only wish i had the room. The only way to achieve that would be to move my garage back haha...and I know my wife won't go for that. I am willing to have to turn them a few times if it means the difference between oven and no oven. The info you showed was very informative as i have not seen that post yet. Like i said, we will be building bigger in the next 2 years once our land is ready. I am just hoping i can increase the dome height in order to increase the door height without having too much of a side affect.

[Lburou]

Originally Posted by Luxy

...snip....Lburou, what size are you planning? And you are going to increase the dome height by 2in?

I plan a 39.25 inch oven floor with about a 21.5 inch dome heigth. A door of about 13 X 18, or, thereabout. I have a week of cold weather delaying the start, so there is a little time to finalize it and then get busy.

[david s]

My oven is only 21" in diam yet is still big enough to fit a 5Kg turkey laying down.

[brickie in oz]

Originally Posted by david s

still big enough to fit a 5Kg turkey laying down.

You or the turkey?

[Luxy]

This is encouraging news. How tall is your opening and is your dome height half your diameter?