So it begins ... (in NZ)

[kiwipete]

I've blatantly pinched the topic title of the thread that Jeff (shuboyje) started some time ago, because I'm in a similar situation to the extent that I'm building my second WFO.

The first one I built provided us with fantastic Neapolitan pizzas but when we sold the house I had to leave it behind 

Then we rented for a while and then started to build our new house. The build was supposed to take 6 months and be nice and easy. In reality, its been 2 years now, still not finished but I''m finally able to start thinking about the outside of the house. Recently we got the patio poured and the pergola is up. So amongst the many other jobs, I've started the foundation for the pizza oven MKll.

I want this to be a low dome one with a 105 cm (41.3") diameter hearth, 40 cm (15.75") height, semi circular opening of 46 cm (18") wide by 23 (9") cm high and a neapolitan style vent.  The wife is worried whether we can still get a roasting tray in an opening of that size (with a small turkey) so her and I might have to have a few more discussions about that.. If anybody with an opening of that size and shape has any experience with getting roasting pans in there and/or using a tuscan grill (like the forno bravo one), please chime in.

With my last build, the oven/vent transition caused me a lot head scratching, so I'm thinking about doing one in steel with the kind help of a mate who does welding. We'll see how we go.

Either way, its been almost four years since I had a really good Neapolitan pizza (my own) so I'm getting pretty anxious. All of my family are super keen for me to build a new oven as well (wonder why?  )

Here are the first couple of pics, nothing exciting yet.

Peter from NZ

[scott123]

That's a great looking spot you have there, Pete. New Zealand is such a beautiful country.

I'm just going to throw this out as food for thought, and you can do whatever you want with it, but, if you have a friend that can weld... you might want to consider a slightly oversized inner and outer door and welding together a throat reducer:

http://www.pizzamaking.com/forum/index.php/topic,21869.0.html

That will give you a nice small opening for Neapolitan pizzas and a larger opening for the bigger stuff.

Is this your first low dome build?

[TXCraig1]

I want this to be a low dome one with a 105 cm (41.3") diameter hearth, 40 cm (15.75") height, semi circular opening of 46 cm (18") wide by 23 (9") cm high and a neapolitan style vent.  The wife is worried whether we can still get a roasting tray in an opening of that size (with a small turkey) so her and I might have to have a few more discussions about that.. If anybody with an opening of that size and shape has any experience with getting roasting pans in there and/or using a tuscan grill (like the forno bravo one), please chime in.

Who cares about a turkey - they roast just fine in the oven - the same can't be said about a NP pie. I don't know about you, but I would regret it every time I even looked at the oven, let alone when I used it, if I made a compromise that negatively impacted the ability to bake NP.

Seriously though, my door is 17.5" wide and 9" high and my 12"x18" roasting pan fits right in. A small turkey wouldn't be a problem. I've made makeshift "Tuscan grills" with bricks and a grate, but in the WFO, I actually prefer to just throw the steaks straight on the coals Joan of Arc style.

[scott123]

Craig makes a good point, Pete. I only tossed out the reducer idea if, for some reason, you're forced into making a large door. I am in no way advocating a large door.

I just read your post again and saw your reference to the Neapolitan vent.  The last time we discussed this it was about 10 against and 1 for (me), and even though I think the vent helps with efficiency, I don't think that it necessarily helps enough to make it worthwhile for a home oven builder.  The low dome is paramount.  Next in importance is a properly sized door.  Compared to these two factors, the vent is, imo, pretty insignificant.

If this were for a commercial operation, I might be the only one pushing for a vent, but for a home oven, I don't think it's worth the hassle.

[dellavecchia]

Beautiful space. Is the wood for the pergola cedar or teak?

John

[shuboyje]

My door is 18 x 8 and although a fraction of the caverns some build on the front of their pompeii ovens I have not found anything I've wanted to put in the oven that has exceeded that size.  I've done Turkey, tuscan grills, roasting in cast iron, bread. 

As somebody who has built an oven with one, I am 100% with Scott on the Neapolitan Vent.  Mine works fine, but not measurably better then the straight up vent in my first oven.  For a home oven I feel the straight up vent provides better thermal properties for basically every function other then Neapolitan pizza, and is much easier to build out of welded steel then a Neapolitan vent would be.

[kiwipete]

Thanks guys.

@Scott: Yes, i have been reading the thread about the reducer and may end up going that way.  
No this is not my first low dome. I've made a "fairly low" dome one a number of years ago, when this was pretty much uncharted territory. I ended up casting the vent for it. I'll attach a pic.
I like the neapolitan vent because a) its traditional and b) because the chimney is at the top and the middle of the oven (rather than the front),  its much easier to build a roof that will shelter me from the the rain because rain or shine, when I've made dough, i'll cook it, regardless of the weather.

@Craig: I'm going to have a look at my array of roasting pans and check out the 12 x 18 ones.

@John: Cedar or Teak? I wish! Teak is pretty much like gold over here. It's treated pine so that hopefully it won't rot. Once its weathered a bit, we'll stain it so it fits better with the joinery. The wife said she wanted a "chunky" pergola, so chunky it will be. The idea is that once we have built the retaining walls (the posts of which you can see in the picture), we'll grow a grapevine over the top of the pergola. That way, we'll have shade in the summer and still plenty of light in the winter.

With regards to the house: if somebody wants to have a look, there are some more pics on: http://s29.beta.photobucket.com/user/kiwipeter/library/House Pictures/

Cheers

Peter

[kiwipete]

For a home oven I feel the straight up vent provides better thermal properties for basically every function other then Neapolitan pizza.

Thanks Jeff.

Would you mind elaborating a bit on the above quote?

(this oven will be used for Neapolitan pizza about 95% or more of the time)

Cheers

Peter

[shuboyje]

Thanks Jeff.

Would you mind elaborating a bit on the above quote?

(this oven will be used for Neapolitan pizza about 95% or more of the time)

Cheers

Peter

With a Neapolitan vent you not only create a large uninsulated section of the ovens dome, you also create an air channel where that uninsulated oven section is actually one of the walls.  When the oven is kicking out tons of hot air running full blast this is fine, and may actually leas to an increased draft(what the Neapolitans claim).  Heat moves from warm to cold driven by temperature difference, the great the difference the more heat moves.  If the oven is hot and the vent is full of hot air from a blazing fire you aren't going to move much heat in either direction and all is good.  Once you slow down the fire or do away with it all together things change.  The heat from your ovens dome will keep the air in the vent warm.  This air will therefore be hotter then the ambient air so you will still have draft.  The vent will draw in ambient air which will then be heated by your dome continuing the process until the heat is gone and the air in the vent is the same temperature as the ambient air.  You've basically convection cooled the oven.  

In the past the idea of a damper in the stack has been thrown around to fix this problem, and although it would help, the oven would still cool faster then a fully insulated oven with a straight up vent due to the lack of insulation.  From my personal experience I also feel a damper in a Neapolitan vent would be a pain to operate.  Reaching the top cent of the oven where the damper would be located requires a ladder and some dexterity.  I work on ladders for a living and can tell you putting the vent pipe on top of my oven is a dangerous and difficult task.  You could put a long handle on the damper to make it easier to reach, but for me that would ruin the ascetics of the oven.

[scott123]

From my personal experience I also feel a damper in a Neapolitan vent would be a pain to operate.  Reaching the top cent of the oven where the damper would be located requires a ladder and some dexterity.  I work on ladders for a living and can tell you putting the vent pipe on top of my oven is a dangerous and difficult task.  You could put a long handle on the damper to make it easier to reach, but for me that would ruin the ascetics of the oven.

When I recommended the damper earlier, I was picturing the kind of damper that can be manipulated with a long pole.

[kiwipete]

With a Neapolitan vent you not only create a large uninsulated section of the ovens dome, you also create an air channel where that uninsulated oven section is actually one of the walls.  When the oven is kicking out tons of hot air running full blast this is fine, and may actually leas to an increased draft(what the Neapolitans claim).  Heat moves from warm to cold driven by temperature difference, the great the difference the more heat moves.  If the oven is hot and the vent is full of hot air from a blazing fire you aren't going to move much heat in either direction and all is good.  Once you slow down the fire or do away with it all together things change.  The heat from your ovens dome will keep the air in the vent warm.  This air will therefore be hotter then the ambient air so you will still have draft.  The vent will draw in ambient air which will then be heated by your dome continuing the process until the heat is gone and the air in the vent is the same temperature as the ambient air.  You've basically convection cooled the oven.  

In the past the idea of a damper in the stack has been thrown around to fix this problem, and although it would help, the oven would still cool faster then a fully insulated oven with a straight up vent due to the lack of insulation.  From my personal experience I also feel a damper in a Neapolitan vent would be a pain to operate.  Reaching the top cent of the oven where the damper would be located requires a ladder and some dexterity.  I work on ladders for a living and can tell you putting the vent pipe on top of my oven is a dangerous and difficult task.  You could put a long handle on the damper to make it easier to reach, but for me that would ruin the ascetics of the oven.

If I remember correctly, you have given your oven a bit of an overhaul a little while ago and where thinking about changing vent types at that stage. So, assuming you've stuck with the Neapolitan vent and given the above, what were your reasons for sticking with it?

Peter

[shuboyje]

I stuck with it basically because it was already built and would be one less change.  If building a home oven from scratch I would vent similar to Cirigliano Forni's front vented ovens at this point. 

[Tscarborough]

One other advantage to a Neapolitan vent is better access to the oven.

[shuboyje]

That depends on how you build it.  The traditional Neapolitan oven is completely devoid of insulation on the front, which is also not something I would do in a home oven that will be fired infrequently(not daily for a commercial oven).  I chose to insulate both outside of the mass on the front of my oven and outside of the front of the vent.  I would recommend that method for any home builder, and in that case the neapolitan style vent and the straight up vent would offer equal access.  

edited to add a quick drawing: 
To help explain a bit more, a picture is worth a thousand words.  The left is a Neapolitan oven, the Right is my oven.  As you can see done my way with the vent inside the insulation it doesn't matter if you go straight up or over the top, you still end up with the same short 6" landing in front of the oven and great access.

[kiwipete]

That depends on how you build it.  The traditional Neapolitan oven is completely devoid of insulation on the front, which is also not something I would do in a home oven that will be fired infrequently(not daily for a commercial oven).  I chose to insulate both outside of the mass on the front of my oven and outside of the front of the vent.  I would recommend that method for any home builder, and in that case the neapolitan style vent and the straight up vent would offer equal access.  

edited to add a quick drawing: 
To help explain a bit more, a picture is worth a thousand words.  The left is a Neapolitan oven, the Right is my oven.  As you can see done my way with the vent inside the insulation it doesn't matter if you go straight up or over the top, you still end up with the same short 6" landing in front of the oven and great access.

I really like how have done your cast oven opening and have been drooling over some of the pics of it. But when I started thinking about how I was going to make a mould that would incorporate the various curves, I came to the conclusion, that it's beyond my current skill set.

After you mentioned Cirigliano Forni's front vented oven, I had a look at some pictures of those and quite like the idea of them, but it will probably start looking more like the oven on the left in your drawing.

Peter

[kiwipete]

Question for Jeff:

You mentioned in the thread about the "FGM Modified throat" that your first, smaller oven had 3" mass in the dome. (as did my first one). You also mentioned that your new one has 4.5" (half brick) thickness  and made some comments about the difference in heat up time between the two with the newer one taking much longer.

Dome thickness vs heat up time is one of the things that I have been thinking about.

I'm presuming that heat up time is a function of a) the mass and b) the door opening but I'm not sure how much each of those factors contributes to the heat up time.

If you were to build a 42" oven again, would you still go with 4.5" or maybe something in between like 3.75" (which would a bit wasteful because medium duty firebricks are about NZD 7.00 a piece)?

Peter

PS Of course any heat up time, be it long or short, can be put to good use by consuming a quality red wine, so a longer heat up time is not completely wasted (as TXCraig has pointed out before..)

[Tscarborough]

I meant side to side.

[Tscarborough]

My theory of mass is simple:  What are you going to use it for?

If for a lot of parties, and extended cooking, then more mass.

If for a couple of pizzas with an occasional party and not much extended cooking, then thinner is better to a point.

[kiwipete]

Small update.

Block work for the base done, rebar in, holes filled with concrete.

In case somebody is wondering what the two cut outs in the top of the back wall are for: since I've had to leave my first pizza oven behind when we sold the house (and I hated having to do that), I decided to make this one "portable". I'll put some galvanised flashing on top of the base, just to cover the width of the blocks, so that the concrete hearth slab will just "sit" on there without being stuck to the base.

If I want to take it away to somewhere else, I can just shove two steel beams underneath and then lift it up that way.

Peter

[kiwipete]

This is the intended profile and dimensions for the oven:

(door opening is 46 x 23 cm)