Author Topic: Who sells metal arch doorways?  (Read 2510 times)

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Offline pacoast

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Who sells metal arch doorways?
« on: August 10, 2009, 04:02:11 PM »
I'm trying to find some vendors for two pieces I need to build a Neapolitan oven. Looking for a 43" round tile floor and the distinctive metal arch that surrounds the doorway on most Neapolitan ovens. You can see both in the picture below.

These are easily available in Italy, but I'm having more trouble finding them in the US. Especially the metal arch for which I haven't been able to find a stateside vendor for yet. Any ideas?

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Offline Matthew

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Re: Who sells metal arch doorways?
« Reply #1 on: August 10, 2009, 06:37:39 PM »
I'm trying to find some vendors for two pieces I need to build a Neapolitan oven. Looking for a 43" round tile floor and the distinctive metal arch that surrounds the doorway on most Neapolitan ovens. You can see both in the picture below.

These are easily available in Italy, but I'm having more trouble finding them in the US. Especially the metal arch for which I haven't been able to find a stateside vendor for yet. Any ideas?

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The metal arch could be easily fabricated by a metal worker if you had the specifications for it.  Your issue is the cooking plain/floor.  The one in the photograph is comprised of "Biscotto di Sorrento". Biscotto di Sorrento is a particular brick which is made from clay with refractory characteristics from Sorrento, Italy.   If this is the floor that you are after, you don't have a choice but to import it.

Matt
« Last Edit: August 10, 2009, 06:41:24 PM by Matthew »

Offline pacoast

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Re: Who sells metal arch doorways?
« Reply #2 on: August 10, 2009, 08:30:09 PM »
Thanks Matthew. It is indeed Biscotto di Sorrento or Sorrento clay tile in the photo. Certainly authentic, but it's rather expensive to import one floor at a time. So I may have to go with an approximation. Similar floors are used by Mugnaini (Valoriani) & the Forno Bravo ovens amongst others. I'm waiting to hear whether these firms will sell the floor tile separately or not.

I'd think that someone on this side of the ocean would be selling the vent (metal doorway arch) though. It's cast iron, with a typical opening of about 22 x 44cm. Acutno is one well known brand. I had a welder estimate $100 - $150 for time & materials. But a production piece probably has better finishing & may well cost less than an one-off piece would. So I'm still looking.

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Offline widespreadpizza

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Re: Who sells metal arch doorways?
« Reply #3 on: August 10, 2009, 09:35:36 PM »
  I had some help from 2 stone when I needed a door setup to finish my oven,  the difference is that unlike the archway shown it does not help to support the oven itsef,  although I am sure that could be arranged.  It is a rectangular plate with an arch cut into it with a door that overlays it.  Anyhow I hope 2stone doesnt mind me bringing him up.  I needed a custom piece and he was happy to help.  You can see it in my avatar.  While on the subject of the floor.  I have been thinking about floor material a lot lately.  When I built my oven which I did with a lot of help from the forno bravo site,  I used medium dutyfirebrick as my floor material.  As time has gone by,  I sometimes wonder if it was 100% the right choice.  Anyone have any comments on the differences in performance between firebrick and the biscotto tiles?  Also pacoast,  if and when you get an answer from the people you have contacted to obtain floor material,  I would like to know what they give you for pricing.  Thanks -marc

Offline pacoast

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Re: Who sells metal arch doorways?
« Reply #4 on: August 11, 2009, 01:10:15 AM »
I'm a bit leery of having the vent fabricated because the handful of metalworkers I have spoken to either want to weld the cast iron or use stainless instead. I'm generally fond of stainless, but don't think it will hold up or look as good as cast iron in this role. Welding cast iron is difficult at best & it isn't ductile either. I tried calling a few small foundries but they were either uninterested in casting a single piece or quoted an astronomical price. I suppose I could build a small kiln and sand cast it myself, but I don't have enough time for my existing DIY projects without taking on new ones. Surely someone must sell this type of vent in North America?

As to the cooking floor (hearth), I think that most people use light duty firebrick & by all accounts it works well. Medium duty firebrick has a higher alumina content & is generally not recommended for pizza hearths. It is more resistant to abrasion (good). But it is also more expensive & cited as being too thermally conductive & less resistant to thermal cycling. Are you seeing any spalling or problems with the bottom of the pizza cooking too fast relative to the top?

The refractory floors are from what I am told very similar to low duty firebrick. They are made of similar materials, just cast into large sections. The advantages seem to include less seams, ease of assembly & possibly durability. Biscotto di Sorrento is a premium floor that is used in the best Neapolitan ovens. It is handmade & naturally dried before curing & claimed to be more durable & temperature stable as a result. For Neapolitan ovens it's implied that having Biscotto di Sorrento on a bed of certain soil/salt mix will create a desireable thermal equilibrium for the cooking floor. While it's hard to come by objective & reliable information to compare these materials, the consensus that it works well is such that I'd insist on it for restaurant use. In that context the cost is relatively small compared to many other things. For home use, it remains desireable but on a limited budget, I'd be happy with less iconic brands of refractory tile. I don't have the sense that it is that much better for light usage & would spend more dollars on getting other key elements right, like the dome geometry & venting.

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Offline widespreadpizza

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Re: Who sells metal arch doorways?
« Reply #5 on: August 11, 2009, 08:19:18 AM »
Thanks for the info pacoast.  I am curious though where the information came from,  everything I had read at the time pointed to the use of medium duty bricks and still does in the pompeii oven plans here.  http://www.fornobravo.com/pompeii_oven/pompeii_oven.html  I would like to find out more about this,  as I am not afraid to make some changes to my oven floor for better performance.  Thanks -marc

Offline pacoast

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Re: Who sells metal arch doorways?
« Reply #6 on: August 11, 2009, 03:24:25 PM »
WSP - You probably have the correct or at least most commonly used hearth bricks already. Part of the confusion is that the terminology isn't always consistently applied & it's sometimes difficult to discern which sources can be taken as authoritative. I've spoken to a lot of refractory & chemical engineers and most will suggest that dense firebricks of about 30 - 40% alumina are ideal for pizza hearths. This is the same recommendation that is given in the Pompei oven plans. A few e.g. traditionaloven.com recommend 18 - 28%, but this is the really the recommended ideal for bread ovens. The concern for bread is that the extended contact period with the hearth may burn the crust with higher alumina materials that transfer larger amounts of energy for a given time.

Descriptive labels as opposed to percentages can be misleading though. In Bread Builders, Alan describes standard dense firebrick as 25 - 28% and also refers to it as low duty. What he is calls medium duty firebrick (unspecified, but somewhere between 28 - 60% alumina) is described as being advantageous for pizza but warns that higher duty firebricks are more prone to cracking & spalling. It's unclear if he is referring to firebrick in the 28 - 60% range or just the 60%+ firebricks. My refractories handbook (Schacht) classifies firebrick as 25% (low duty) 29% (med) 37% (high) and 42%+ as super duty. And again gives us a general rule that higher alumina bricks are more prone to spalling from thermal shock. So depending on who you are citing these categories overlap or may label the same product as standard, low duty or medium duty. Note that the common castable refractories that have similar thermal properties to firebrick e.g. Mizzou can have alumina contents in the 60% range, probably making them better suited for the dome walls than hearths. Suffice it to say that almost everyone recommends 30 - 40% alumina for pizza hearths & that is probably what you already have.

Now, could you do better? There appears to be general agreement that the refractory tile floors are better. How much better? My sense is that this advice represents smaller, rather than larger differences. The common tile arrangement is to have a circular floor divided into four 90 quadrants. So being only four pieces it's easier to install & level. You attenuate a theoretical concern that if the bricks/tiles don't have good contact that heat transfer may be uneven. And there are less grooves for a peel to catch on and less edges that might spall or have accelerated abrasive wear. It avoids having to trim bricks to fit within the dome walls. And of course, it costs more. No free lunch for us.

And while almost everyone seems to recommend or prefer refractory tile over firebrick, it's all anedoctal. Firebrick is used industrially, they have to tell us what the composition is. It's difficult to come by technical data such as alumina content, porosity, thermal conductivity, etc for products like Biscotto di Sorrento. You can reasonably infer that it performs well and is durable by the historical use in high volume pizzerias. And it's implied that the skilled Neapolitan oven builders have by experience come to select floor and floor bed materials that create a thermal equilibrium for the floor. But none of this is quantitative. If you find any quantitative data or scholarly research, please pass it along to the rest of us.

For myself, I wouldn't replace a firebrick hearth unless it was mechanically failing or had chronically bad performance. But based on the available evidence, anedoctal & otherwise, I'd prefer to put a refractory tile floor into a new build. And for a commercial venture, I'd hire someone knowledgeable like Marco to erect an authentic Neapolitan oven.

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