sizing help needed

[Forgeblast]

Hi all, I missed a page when I downloaded the instructions/guide. I poured a reinforced and thermal pad that is 49'' wide by 36 1/2'' deep.
I can get (by adding rebar and welding up a frame, and adding on to the pad(i left myself a lip around the pad) 10 more inches across and 9'' forward.
giveing me a grand total of 45 1/2'' deep by 59'' across.
My question(s) is
1. what size oven can i now build with the new dimensions.
2. is there a different type/shape oven that would work on my old pad?
3. any suggestions would be appreciated.
Thank you all in advance for all your help.
(sorry for all the smilies my 2 yo was "helping" me type)

[Faith In Virginia]

Is this what your missing? I may be wrong but it sounds like your small on your dimensions. With what you have stated I think the oven would be too small for any great use. But that is just from what you have stated.
Hope this helps

[azpizzanut]

Hi Forgeblast,

Can you post a few photos of what you've done so far? That will help us to come up with a solution to your challenges.

Cheers,

[Forgeblast]

Here are the pictures.
Picture one shows the oven base, with the reinforced and thermal slab.


Picture two shows the overall placement


one more for good luck

[Forgeblast]

STOVEMASTER - Semi-pre-cast brick ovens
wondering if something like this would fit. it seems to be similar in size, If I take the oven forward 9'' and then add on where the opening and chimney would be the oven would be around 45 x 45 and give me about 2025 square inches of cooking space.
Time to mess around with cardboard.

[azpizzanut]

Hi Forgeblast,

Thanks, the photos help to put things into perspective.

I think you have some major remodeling to do. It may be practical to consider deconstructing the hearth and starting over with the appropriate size while it is still early in the game. Yes, it's a pain ita, but worth the effort. It appears that you've done a nice job on the existing hearth slab so I'm not worried about how a larger rendition will turn out.

In regard to the Stovemaster oven. You are only seeing the finished dome, not the insulation which will add to the width and depth by possibly four inches on each side. Without seeing the completed oven I would venture to say he will use up all the space around it with insulation and enclosure.

My 36" Pompeii oven needed every bit of the 51" wide hearth slab. The external width of a 36" Pompeii oven averages roughly 44" before the addition of insulation. Three or four inches of insulation on each side will bring it up to roughly 52" wide.

I recommend that you re-do the calculation for the 2025 sq in cooking space. I'm thinking you can build a 31" diameter oven (internal dimensions) in the space available if the top slab is 45" x 59". But, it would be oriented all wrong. Where would you place the entrance and chimney? Take another look at the free Pompeii oven plans and see how the slab and oven are oriented. A fresh start will give you the opportunity to approach the build with fewer challenges.

Cheers,

[wotavidone]

I had a surf around the stove master site, and I confess I wish I had not. Very tempting design. Not a dome to satisfy a pompeii purist, but very easy to do.
Essentially a side entry barrel vault, minimal cutting, and no complicated shapes.
If you have already laid a vermicrete floor, they would be very easy to replicate in brick.
And if your base is already insulated, you only need to bed the hearth in clay and get on with laying the dome.
The former would very simple to make from MDF or similar, and if you wanted to, you could just burn the former out later.
I wonder if, I could lay the dome with the 2" clay pavers I can get easily locally, and then lay a chicken wire reinforced layer of homebrew mortar over the whole lot???????. Hmmm........
Local guys who have brick ovens reckon they don't need insulation. Of course around here, the timber falls off the trees (literally, sometimes on your car). Redgums have a nasty habit of dropping branches with zero warning. And the guys I talk to seem not to care about 2 hour heat up times.
My point is, you probaly don't have to have 4" of vermicrete insulation if you are short of space. Maybe a one inch ceramic blanket, with half an inch of render over the top means you only have to lose the thickness of the bricks plus three inches, all up. Say 12 to 15 inches of you 45" slab. So I'm thinking you could just about end up with a 30 inch deep floor. Not big, but more than many commercially available "courtyard" models.
On that score, a FB Primavera 70 would fit, I reckon.
Regards,
Mick

[horrocks007]

The Giardino 60 will fit for sure.

[Forgeblast]

I wish I had the $$ for a precast. Just not happening this year, all on pay freezes.
Mick, do you know off hand the width and height of a barrel vault opening?
or a formula so that i can plan it out.

[wotavidone]

I'm afraid I don't know the answer.
However, it appears to me that the Stovemaster people simply have one opening, one arch former and merely increase the size of their ovens by making each course of brick a bit longer, thus making the oven wider. Their oven size table lists them all as having the same size door opening. I got the calculator out and found their 10 inch opening, with their 17 inch finished inner height, is 59%. So mate, I reckon that's about right. The magic number being 61.8% or 63% depending who you ask, then it would be close, eh? I bet that's the height because thats where the closest uncut brick work ends. Gotta be a bit practical about these things.
If I chose to do this design, I would simply plagiarise their measurements. As long as you are making one only for yourself, are they really going to care? Be a different thing if you were going into competition with them, then no doubt their lawyers would be knocking on your door.
It appears they make a former based on a diameter of about 46 inches, with the floor depth reducing down to 45 inches, because the floor is built up inside the finished vault. Similarly, because the floor is two layers of brick, their finished vault height is 17 inches i.e. the radius minus the thickness of the two layers of brick. Measure the bricks available to you and get the calculator out. The thickness of two layers of brick, plus your desired interior height, dictates the radius on which your former is based. The width of your stand, minus insulation, render and and brick wall thickness x 2, equals maximum length of your former.
I applied the calculator to the openings on the FB ovens as well. They aren't exactly 63% either. I can't stress enough that I have never actually built an oven, very much a beginner like you, but it seems to me, after perusing the published dimensions of lots of well respected brands, that if you have an opening that is between 60 and 70 % of the interior height of the dome/barrel, you should be OK. Same goes for the width of the opening - needs to be wide enough to fit things through and most seem to be about 60 or so % of the interior width.
Naturally, you won't be buying precast end pieces. Note these guys build the oven then slide the former out and fit the other end wall.
Assuming you'll use brick like I would, you'd make your former, which appears to be very thin MDF bent over frames, to exactly the interior size of your oven, not forgetting to allow for the thickness of the floor bricks, leave it in and burn it out slowly when you cure your oven.

One change I'd consider compared to theirs.
The piece of angle iron they use for a lintel over the opening.
Since I would be using ordinary bricks, not lovely wedge shaped ones like these guys, and lime mortar, because anything else over here is very expensive, I'd consider putting it under the brick, not over like they do. Also, I'd carry it right through to the side walls so it sits on the side walls for support. And I'd make sure there is nothing obstructing the ends, so it can expand lengthways as it gets hot.
Do not take my word for it though. I am unsure how much the steel would warp and corrode in the heat, and it may be better do do it their way so that the brick protects the steel a bit. One thing I do actually have a little bit of hope of getting cheaply is stainless steel angle. I don't know how it performs in the heat, though. I'm sure there will be opinions offered shortly
Man, I wish someone had already done one of these. I shall search youtube. I want to see if they get hot enough for a 90 second pizza.
Enough of my ramblings. Hope this has been of some help.
Regards,
Mick