Feeling brave... a true Neopolitan Pizza Oven

[Orbaram15]

Re: Feeling brave... a true Neopolitan Pizza Oven

Hi man you instructions how to build the Neapolitan dome and the materials and all of that.

[Hendo]

Re: Feeling brave... a true Neopolitan Pizza Oven

John,

Thanks for the info on your build. The smooth exterior of the buttress hides a lot of work (and challenges no doubt!). Did you take any photo?s of this stage of construction? I?d sure like to see them if you did.

Cheers, Paul.

[maver]

Re: Feeling brave... a true Neopolitan Pizza Oven

JB - truly impressive. I see you acknowledge a professional oven builder for direction in engineering your dome - thank the builder for us for sharing with you these techniques. I don't know that anyone here has done anything similar to this with either the portland/sand mix or the insulating concrete buttress reinforced with plenty of rebar/galvanized fencing. The interior looks terrific as well. Am I seeing it correctly that the heatstop bulged through on some of the joints? Even so, there do not appear to be any sharp angles that will be overexposed to heat, I doubt you'll have any mortar spalling problems. Looking forward to hearing your cooking experiences!

[johnrbek]

Re: Feeling brave... a true Neopolitan Pizza Oven

Hendo,

Brick depth on the dome and soldiers = approx 3", the hearth bricks are 2 1/8", which resulted from bricks that were locally available.

The buttress system is 5" thick. It is poured from a thick mixture of Kast-o-lite 22 (hereafter referred to as > KOL22), a 2200 degree insulating castable refractory. I debated going with a Perlcrete mixture, but since I was already placing a pallet shipped order for castable refractory (for the flue construction) and steel needles, I decided to go with Kast-o-lite on the recommendation of my builder contact. I suspect a Perlcrete or Vermiculite concrete mixed might reinforce in a similar manner, but it would need to have been tested and I wasn't in the mood to mess around with that. Beyond that, the idea is to keep heat in. The insulative value of Kast-o-lite products is way better than Perlcrete..

As I said, the KOL22 is 5" thick. It sits on top of the Insblok 19 (simply because I didn't want to run out by pouring it directly on the concrete slab.. wasn't sure I had enough) and the aluminum foil is only there to minimize the Insblok from sucking up the moisture from the wet Kast-o-lite mix till it cured.

Within the 5" KOL are 14" high pieces of 5/8" rebar that are sitting vertically in holes drilled through the Insblock down 2" into my concrete slab.... The rebar pieces are placed every 10" around the entire perimeter. Then several 4' long 3/8" rebar rods were bent to match the shape of the perimeter and placed and tied to the vertical 5/8" rebar pieces with rebar tie wire. If that weren't enough, I then took some extra 1" x 1/2" galvanized fence wire and wrapped that on the outside of the rebar... This whole reinforcing structure sits about 2" outside the soldiers (in the middle of the KOL22 pour...)... Once the rebar structure was in place, I used the same 1/4" fiberboard I used to support the sand dome (which bends really easily and is pretty strong) to create a form... I used L brackets and tap cons drilled into the concrete slab and the fiberboard to affix it in place along the bottom and a couple cargo straps to keep the form in place up top... I then mixed the KOL22 according to directions and poured.. It's a really thick mix, so read the directions if you go that way...

Yes, I think the vanes are polystyrene.. the are about 1/2" thick and available at Home Depot (our big home improvement store here in the states..).. you can buy 4'x8' sheets for about $8. These vanes were only used to set the arch and help maintain the arch as the sand form was being laid...

I wouldn't say knocking out the sand form was extremely difficult, but it wasn't a piece of cake either... Since the vanes are in there, you really have 4 sand dome quadrants if you will.. They tough thing about knocking it out is taking the bricks it's setting on out.. That sand form is heavy... Once you get most of them out, it just falls to the hearth floor and you can smack it around with some rebar or something and knock it apart in chunks... Others may have a more ideal sand/portland ratio.. I thought my ratio worked well.. It was soft enough to shave the shape as construction took place and hard enough to maintain shape under pressure and the repeated knocks of the end of my trowel against each brick as I placed it.. I suspect if you went too light on the portland, you have a less stable dome that might start to break apart as you bang your bricks in place... the challenge (for me at least was) the working time you have with Heatstop 50 (the refractory mortar).. the more it begins to set as you're working with it, the harder you have to bang your bricks in place for a tight fit and the more that sand dome needs to be able to stand up to it...

Thanks for the complements.. I'm happy to have gotten this far.. and again, I've learned a lot here and appreciate the advice I've received from some of the guys here along the way... My challenge is time.. I'm in software sales and I travel alot, so I don't get to work on the oven as much as I'd like... As I write this post, I'm sitting in a hotel room in Guanajuato, Mexico. Really cool town to visit if you ever get the chance...

JB

[Hendo]

Re: Feeling brave... a true Neopolitan Pizza Oven

John,

Superb effort! It really does look splendid. All the cuts have clearly resulted in minimal mortar joints, which should auger well for a solid, stable structure.

I have a few questions though (apologies if I've missed the answers in previous posts, which I've been following with great interest).

You've used 3" thick firebrick for the dome, but how thick is the insulating buttress and from what is it made? Are the soldier course and floor also 3"?

You've mentioned elsewhere that the soldier course of the dome surrounds the floor, and both are laid on a 2" thickness of "insblok 19". What is the buttress sitting on?

How far does the aluminium foil (first photo) extend and what is its purpose?

Are those white lines polystyrene foam 'vanes'? You've mentioned that you used "150-200lbs of sand to 1 good shovel full of portland" for the sand mold - was water added (how much?) and was it difficult to knock out afterwards? I'm trying to visualise getting rid of a solid mass of concrete!

Can't wait to see the finished oven.

Cheers, Paul.

[johnrbek]

Low Dome Neapolitan Oven Update..

Well, it's been a couple months and I've finally finished the core of the dome. I will begin building the oven landing, flue, and chimney next.

Below are a few pics I threw together for those interested.

Happy to answer any questions.

Low Dome Neapolitan Oven Update - Dome Construction. Photo Gallery by John Bek at pbase.com

[johnrbek]

Re: Feeling brave... a true Neopolitan Pizza Oven

aeneas,

With respect...

There's no debate that there is a Neapolitan style pizza oven, just as there is a very well defined Neapolitan style pizza. This has been documented both here on Forno Bravo, on pizzamaking.com, as well as other places such as VPN Americas (LLC) - The Verace Pizza Napoletana Association in the Americas. Do a little poking around on these sites or shoot me an email if you'd like to discuss details....

The purpose of my post is not to debate this restaurants oven or that restaurants recipe. Rather, my purpose is to document my journey building a Neapolitan style oven, to solicit advice from knowledgable builders here, and to shed some light on some of the design aspects, construction methods, and perhaps pitfalls of this type of oven that to date are somewhat of a closely held secret.

I'd like to keep the dialogue going, but I'd rather we stay on topic. If you'd like to debate these points or take it in another direction, I'd be happy to, but I'd prefer to do it under another thread or via email if that's okay...

Good Karma! Thanks!!

JB

[aeneas1]

Re: Feeling brave... a true Neopolitan Pizza Oven

very interesting discussion -

when it comes to "true" pizza napoletana (be it ovens, preparation, ingredients, etc.) it seems that, in the final analysis, "true" exists only in the eye of the beholder.

for example, drizzling italian evo on the pizza prior to placing it in the oven, or using evo in general, is said to be traditional when it comes to neapolitan pizzas. yet da michele's, arguably the best and most traditional pizza napoletana in naples, doesn't use olive oil at all - they use soya bean oil. nor do they use buffalo mozzarella. is it possible to produce a "true" margherita without evo and buffalo mozzarella? apparently so unless one doubts the authenticity of da michele's pies.

and what about una pizzeria napoletana in new york, arguably the best authentic neapolitan pizza in the states? looking at available internet photos of their oven, it doesn't appear to be a low-domed "true/authentic" neapolitan oven (nor does the one used at da michele's for that matter) - of course i'm not certain that this is the case but there are a few photos out there in which the flames seem to be more consistent with a higher dome. should it in fact be the case, i.e., both places using higher-domed ovens similar to those offered by forno bravo, would it make their pizzas any less authentic?

[johnrbek]

Re: Feeling brave... a true Neopolitan Pizza Oven

Yep.. will do on the milestone pics... thought about that... links do die and it sucks 3 years later when you come along and you come up with a dead link..

Gonna go post a forno bravo link right now...

[james]

Re: Feeling brave... a true Neopolitan Pizza Oven

Looks great. I think everyone would also appreciate it if you could post some of your better milestone photos in the FB Forum gallery. That would be really helpful.

Also, I would appreciate it if you could link for Forno Bravo on your Photo Gallery. That would help other builders find us. Thanks.
James

[johnrbek]

Re: Feeling brave... a true Neopolitan Pizza Oven

Thanks for the detail James.. I think that clear's it up for me... I'm gonna have to give it some thought to see which way I go...

I'm still in the more mundane part of the build, but here's a progress update:

Neopolitan Pizza Oven Project Photo Gallery by John Bek at pbase.com

Later...

JB

[james]

Re: Feeling brave... a true Neopolitan Pizza Oven

JB,

Good question. There are two potential landings in the front of your oven. There is the vent landing, where your vent is framed, with the oven landing beyond that.

The vent landing walls can be 4" deep because the chimney itself can be set back from the front of the oven. It sits above the dome. Take a look at the Casa installation guide for some ideas on that. It goes up and back. If you would rather go straight up, and leave 10" for the vent beyond the front of the oven chamber (to allow for the anchor plate), that would work as well.

Also, it's good to note that there are a number of vent designs. You can attach the vent to the upper oven enclosure and not use vent walls. If you pick that method, your vent landing and the vent itself are completely detached. They are not tied together in terms of size. The vent landing/oven landing can be any size you choose. This is both functional and decorative, but it is not tied to the size, or dimension of the vent.

In terms of chimney size, you are in good shape with 8". We sell fully assembled ovens (the Modena with a 16.5" high dome) that is much larger than the oven you are building, that has an 8" (20cm) chimney adapter.

Keep going!
James

[johnrbek]

Re: Feeling brave... a true Neopolitan Pizza Oven

ljanmi2,

Your conclusions regarding dimensions and ratio's seem pretty solid and I think my final dimensions will be similar to yours, but I I"ll be going with the 42" inside diameter... Here's what I'm thinking:

42" inside diameter
14" interior ceiling
17" wide opening (half circle)
9" high opening (half circle)

The 14" interior height is 1/3 the diameter and the 9" high opening is about 62% of interior height. BTW, I think your right about Pizzanapoletana assuming the 120cm when plotting out his dimensions and ratios...

Haven't decided on the opening yet... did notice that feature on the Neopolitan ovens I've seen photo's of... If I go with metal, I think I'll need to fabricate something out of stainless steel (I'm down in S Florida).. I would think just going with brick or some other attractive stone (for the outside arch) would be pretty easy...

On another note, since the concrete truck is coming tomorrow and I need to go put some rebar in the right places to tie into the block walls (florida building code), I have a question about dimensions:

In James dimensions here: http://www.fornobravo.com/pompeii_oven/dimensions.html

.. he indicates the "vent landing" depth at 4".... I'm confused by that.. I was think of going with 8" duratech pipes and casting the transacton piece to meet up with Simpson's #9541 anchor plate which is 8" in diameter... My vent casting would then need to be at least as wide as my opening, 8", and just as deep if not more deep than 8" the duratech pipe will take.. Maybe 10-12" deep... so in my mind, the vent dimensions need to be about 10" x 12"...

Questions:

1. How can be vent landing depth be 4" if we need about 10-12" of depth there in the transition to meet our 8" pipe? Am I missing something?

2. For the 42" oven is the 8" duratech enough diameter? I'll get into my design in more detail later, but I'll be routing the chimney pipe up over the top of my oven (at a 45 degr angle I suppose) so the chimney is literally in the back of the oven... My front of my oven will be under a covered patio, so I don't want smoke coming out of the front of the oven opening and into the patio... The chimney will progress 3' above my roof line, so I'm confident I"ll have a good long run to promote suction, but is the 8" enough?

The vent landing question is an immediate concern as I think it affects the size of the stand and thus where I need to sink rebar today before the pour tomorrow..

JB

[ljanmi2]

Re: Feeling brave... a true Neopolitan Pizza Oven

Good news, I now know that am not alone in wanting to build the Napolitan style low ceiling oven.

Just like you did, I have too researched postings by pizzanapoletana and found his recipe (height = diameter / 3.4) for height/diameter ratio of 29.41%. When he posted it, I beleive that he actually had the 120cm diameter in mind. Now, if that ratio is used for smaller oven sizes it quickly becomes obvious that such low ceiling would not work.

My thinking is that what is important in Napoletan design is the distance from floor to ceiling and shape somewhat. I beleive that this is needed in order to achieve the goal of having both top and bottom baked at the same time. If ceiling is lowered even more when reducing diameter this balance would be disturbed.

Based on this thinking, the idea I have is too keep the door size, ceiling height and height of the vertical part of the dome the same as original 120cm oven size, but scale the diameter to more practical (for home use) 36" and go with the 3" wall thickness.

I have attached drawings that I made during my research, and as you can see KiwiPete's oven is VERY close to what I came up with. It seems that he did not have any problems with his dome, which is the most radical (in the height/diameter ratio sense) that I was able to find on FornoBravo site.

Now that you posted your calculations I can see that Volta Bassa standard ceiling height posted by James matches my calclulations of dome ceiling height exactly (which is 120cm/3.4 = 35.3cm = 13.9").

Are you planning to use sheet metal door oppening (like visible on pictures posted by pizzanapoletana) or build it with bricks?

[james]

Re: Feeling brave... a true Neopolitan Pizza Oven

I like the idea of "de-mystifying" this oven -- all wood-fired ovens for that matter. I think in the era of YouTube, Wiki and Forums (hey, we were all Time Man of Year), that sharing ideas, learning how to do new things, and lifting the veil on otherwise hidden concepts is a powerful thing.

Tufa is the local volcanic ash that they use to insulate the Naples ovens.

Mt. Vesuvious has a lot to do with all of this. The water in Naples is very soft, as it goes through a huge natural brita filter to reach the water table, which helps make the pizza dough. The soil is also perfect for San Marzano tomatoes. Pozzolana, the active ingredient in Roman concrete that was capable of setting underwater (and lasts for 2,000 years) come from quarries near the Bay of Naples. Naples is the perfect pizza storm.

Enjoy. We will look forward to photos, as well as video (I hope).
James