Neapolitan oven - lower dome height

[Muscats]

Hi everyone;

I will be starting an oven in the near future and have a few technical question to settle things in my mind before I get started.

So my first question is about dome shape and lowering the dome height.

I plan on using the "Indispensable Tool" and have read a few posts about its use and the tendency for it to make the dome slight high due to the hinge making the base of the tool higher than the floor of the oven.
So is it logical that if I make the attachment point for the tool lower than the floor of the oven I would get a corresponding lower overall dome height while keeping the dome symmetrical?

Paul

p.s. this build will be in Burra NSW just south of Canberra Australia

[fxpose]

Re: Neapolitan oven - lower dome height

Hi, I plan on using an off-center axis guide (for the first few courses up) to achieve the lower dome height. I'm using a gate hinge to keep the hinge point as close to the floor as possible.
I will assemble the tool this weekend.

Here's a couple of crude drawings of the tool I posted here a few months back (except I won't be using a lazy suzan, as it adds additional height to the tool):

[david s]

Re: Neapolitan oven - lower dome height

If you remove some of the bricks in the centre of the oven and even chip away some of the vermicrete insulation, then the base of your tool could be located a lot lower, but you then have to replace insulation and bricks so the floor is level.

[Muscats]

Re: Neapolitan oven - lower dome height

thanks for the replys

fxpose, I was looking at the lazy suzan option but was unsure about the resulting flat centre.

David s, your idea is the one I was leaning towards. My oven will have insulation bricks under the floor, so no need to chip away the insualtion layer and it should be easier to replace the insulation bricks and floor tiles while still maintaining a level floor. The only issue I see is that I will probably have to make and Indispensable Tool with a bend in it to avoid removing too many tiles and bricks

I have attached a sketch of how I was thinking it would work

Paul

[david s]

Re: Neapolitan oven - lower dome height

Looks like an ideal solution.

[shuboyje]

Re: Neapolitan oven - lower dome height

To me that seems like extra work and potential for a uneven floor without any real gain. IMHO a slightly lower hemispherical dome doesn't sound like what you are after. If you want more of a naples style oven you need a tall soldier course and a very flat roof. If you don't want to go to that extent and deal with the issues it creates(Indispensable Tool doesn't really work, need to support the lateral force of the dome on the soldier course, etc.)then you are probably best off following the beaten path. For reference my oven is a tiny 30" with a 7.5 inch soldier course and a 13.5 inch dome height. I am currently planning a bigger oven and will go even lower with a 48" oven having a 10 inch soldier and a 14" dome height. None of this leads to a true Naples shaped oven, you aren't gonna find that info online, but it would get you closer then what you've proposed.

[david s]

Re: Neapolitan oven - lower dome height

Another solution is to simply build a sand castle of the required form over the floor and lay the bricks up to the sand. when done you dig the sand out the door. Shaping the form is actually quite easy and with some taps of the flat of a trowel you can get it smooth and accurate. I read somewhere that 10% water (by volume) is about the correct mixture.

[100million]

Re: Neapolitan oven - lower dome height

Paul look at my build I have low ceiling for pizza oven

All I used to set the height of the bricks for each row is A piece of sheet rock

What we did is this

We draw found the height we wanted and then draw the shape of half of the dome on a table....A cross cut section of it ....This allowed us to find each angle of each row before we started making the rows.... Then what we did is cut one stone for each row and placed it on the table .....then what we did is this we took a piece of sheet rock and carved the exact shape of the doom and then we mark ever angle and height of each row on the sheet rock.... then after we made the 1st solider row we had a mark of how high the next row and what angle it needed to be.....It is not rocket science to keep the cut bricks in place with the 1/4 shape of the doom ( piece of sheet rock ).

If you have any question about this just ask it was easy and if you look at the inside of our doom it is SWEET and as perfect as a imperfect man can do.

I know there are perfect women out there but that is another story

http://www.fornobravo.com/forum/f8/b...oor-12363.html

[dmun]

Re: Neapolitan oven - lower dome height

Muscat's idea of a radius beneath the floor will work to create a sphere segment, but if you want a truly elliptical dome, the bricks will not point to a single point. If you try with a variable length indispensable tool, you'll end up with stepped courses, although it may be too subtle to make a difference. I've tried to wrap my head around a double jointed tool that would mimic the focii of an ellipse, but the problem eludes me at the moment.

[david s]

Re: Neapolitan oven - lower dome height

Remember too that the most efficient combustion chamber is the hemisphere. Any departure from it is a compromise. It's like boats, there is no perfect form. The form you choose is a compromise to suit your needs.

[Muscats]

Re: Neapolitan oven - lower dome height

david s;

yes, I agree about the hemisphere being more perfect, and if you follow the arguments re heating and radiated heat the perfect hemisphere is supposed to do the best job by heating more evenly and radiating in all directions.
That is why I thought the idea of lowering the focus of the sphere would achieve three aims. It would keep the nice hemispherical shape I wanted, and keep the top of the dome reasonably low, while still providing a 42" floor.

Paul

[david s]

Re: Neapolitan oven - lower dome height

I agree entirely, however some folk like the vertical sides at the base, so it gives them more room at the edges. Personally I like the traditional hemisphere, it served the aancient Romans well for thousands of years, that's good enough for me and I like knowing I'm part of a long tradition. My wife and I are visiting Italy in October and amongst other things, I'm excited about visiting Pompei.

[Muscats]

Re: Neapolitan oven - lower dome height

you lucky bugger, make sure you bring back plenty of authentic reciepts

[david s]

Re: Neapolitan oven - lower dome height

I'm an art teacher and we now have to keep a register for PD (30 Hrs/year)otherwise we can be de-registered. I think I will tell them to stick it and keep all my gallery receipts. That should be sufficient. After Italy in October we travel through Switzerland by rail to Provance, France for self guided cycle tour through all the van Gogh country then on to Loire valley for a week, Then on to UK and Ireland by car, return to the tropical heat of Townsville for early Dec. I'm excited!

[dsgreco]

Re: Neapolitan oven - lower dome height

I am building a lower dome 36" oven. My diameter is 36" but my final interior height will be 15.5". I have made an indespensible tool that has an adjustment for length and I had to bend the end as well. I am working on the second course now and it seems to be working out ok. As I get into the upper courses we will see if the design works.