Oven building

[Acoma]

I have read countless threads and posts regarding oven building by many of you. In the beginning I was very nervous about such an endeavor; yet now, I am much more confident. I do have to ask how some of you have built your pizza ovens with no real room for the vermiculite. I have seen James state the the way to build is to have the dome, then 1" insulfrix, then 4" of loose vermiculite (5" in back). Several ovens seem to be skimping the 4" vermiculite part, why? I hope I am not out of line here? My goal is to build one too. Some of you have built 42" ones, would you wish for bigger, say 50" or so, and why? Is the 42" plenty? As for the flute, why not move it towards the back, similar to Peter Moore's designs? It appears that no forms for the dome is much better when it comes to having a clean interior dome. My goal is for a Tuscan style, 42-50". I know I have asked a lot of questions, but I must decide on my foundation quickly. I also have a quality charcoal grill and smoker that will be part of the designed area too. Sorry for the first post being this way. I will also show progress over time as I get things going.

-Rob

[dmun]

Hi, Rob, Welcome.

First, and most basic, the flue question. You are trying to heat (and keep hot) the oven, not the chimney. If you have the flue in the rear of the oven, the air will enter the front, combust with the wood, and quickly exit in a straight line out the rear flue. The front flue causes a circular air path where air comes in across the floor, combusts, and circles around the top of the dome, bringing it to heat the oven chamber before exiting, somewhat cooler, up the front flue. I once saw a diagram on a wood oven site that explained it well, and browsing around looking for it just now i found pictures of this rear flue oven. The bottom line is wood, and time. The oven I linked to would, I guess, burn cords of wood and achieve pizza temperatures slowly, if at all. The other problem with the flue-in-the-oven system of any sort is that you can't easily close off the baking chamber for retained heat cooking.

Refractory blanket insulation is more efficient and more expensive than vermiculite/perlite concrete. If you have more room, you can save a little money. If space is a problem, you can use more Insulfrax and leave out the vermiculite entirely. Your choice: both work well.

42 inches is plenty big for a residential oven. Bigger ovens are used in commercial pizza operations, but they keep them fired every day. Most of us want an oven that heats up quickly near dinner time to make a few pizzas. A bigger oven needs a bigger workspace and more workers: you can cook six pizzas at once, but can you make them and serve them that fast? Probably not. Remember, a wood fired oven cooks a pizza in a couple of minutes or less.

Good luck with your project.

[Archena]

Oooh! Thanks for the link! That's one serious stand - but it shows the footings I'd been considering so it's really nice to see - thanks.


Getting out of the way now....

[wlively]

Agree with Dmun, 42" is plenty. I can fit more pizza's in my oven than I can make at one time.

Always use the most insulation you can afford, both $$ and space. You can never have enough.

[n2iko]

I believe Rob was referring to this as a rear chimney:
MHA News - 2006 Meeting - Backyard Oven with Peter Moore

--mr.jim

[Acoma]

Thanks for confirming 42" round base. I will go with the idea of the formula James showed us per the PDF on a building one. James mentions 6" vent, wouldn't smoke still have opportunity to come out the face. I see on Drakes "Drake's 38: oven" thread that he has a larger vent. I do not wish to have one that is too big, only one that will maintain correct path of smoke (up the flue). As for my comment about Peter Moore's rear flue, I wish to clarify. The vent is in the front, runs up the dome towards the rear area, then the flue goes vertical from there. Also, I will not be creating a fish with my design eiher . I was thinking of a gap at the landing area for cleaning, what ideas exist for that?

Robert

[Acoma]

Mr. Jim, you are correct. That is what I mean by rear flue.

[james]

You definitely can pull your vent back over the top of the dome. There are a handful of Pompeii ovens that have been done that way -- and many of the pizzeria ovens in Naples city are done that way, though not many in other part of Italy. There is some question as to whether the pulled back vent is decorative or functional. Some folks think having the hot air run back over the top of the dome helps keep the oven hot, but given the high BTUs put out by the fire, and the relative coolness of the vent compared with the oven chamber, I'm not sure it has much of an impact.

You can use metal pipe to pull the vent back to the center as well. It's easy to do and looks nice. I've done that myself.
James

[Acoma]

James, do you have any photos to show your work with the vent back over the dome? Also, how many inches from stand to foundation edge would you recommend for stone work? 4" per side?