Valoriani 100 Sydney Build

[PizzaCharlie]

Hi All,

About to build a Valoriani 100cm kit oven.
At the moment it's still packed in the backyard but just wanting preliminary feedback and advice to minimise future problems. Excuse my lack of proper oven building terminology.

This oven will be on a metal stand.

First off I'd like to get advice on the base. As it stands now I'm thinking of building it on top of a cement fibre sheet, above that 50mm concrete, above that will be 50mm of hebel brick and finally the oven floor.
Attached is a picture to make sense of it all.



From your expertise and experience, how is the base looking?

Charlie

[Toomulla]

Re: Valoriani 100 Sydney Build

I recommend that the concrete be 100mm. 50 mm is no more then a concrete paver and will not provide either the strength or cover to the reinforcing

[cobblerdave]

Re: Valoriani 100 Sydney Build

G'day
I'd lose the concrete layer. Lay the compressed sheet on angle steel joists at 300 mm centres. The sheet and the hebel will carry the weight of the oven. The oven may be heavy but that weight is spread over a large area. I'd be more worried about the strength of the stand legs and the cross bracing.
Regards dave

[BrendanLovesPizza]

Re: Valoriani 100 Sydney Build

At least one layer of reo mesh, with 100mm squares, otherwise two layers of 200mm squares, with a 95mm slab is strong enough. Then the concreete has to be at least a 20-32 mpa. Are you making the slab yourself or getting it poured?

[cobblerdave]

Re: Valoriani 100 Sydney Build

G'day
http://www.fornobravo.com/forum/51/n...tml#post143730
Hebel oven stand
http://www.fornobravo.com/forum/f6/3...tml#post149565
Oven on a compressed cement base

Both will work why add a cement top as well? The very least you'll have to beef up the legs to carry the extra weight
Regards dave

[PizzaCharlie]

Re: Valoriani 100 Sydney Build

Interesting. So I get 2 different suggestions. Two with 100mm cement and the other without.

This stand is going to be on wheels, so I will need to factor in the overall weight of the oven+stand.

My bro in law is a concrete truck driver so I got access to hard cement.

What is the overall role of the cement slab anyway? Is it just to hold up the hebel bricks or does it offer some insulation?

Would it be any different if I stack up a few cement sheets on top of each other rather than pour a cement slab?

[seamad]

Re: Valoriani 100 Sydney Build

If you ask for advice you're going to get different opinions, everyone here has approached their builds from different angles. Mine is different again but similar in some ways to what you are planning. I welded up a steel frame then bonded hebel power panels to the steel, then ceramic insulation on top of the hebel. It's not on wheels though, way to heavy.
What model do you have ? Had a look at the website and they have a few different 100cm ones. One was 600kg, hope you haven't got that one.

[PizzaCharlie]

Re: Valoriani 100 Sydney Build

I got the fvr100.
Heavy thing.

[cobblerdave]

Re: Valoriani 100 Sydney Build

G'day
Again I get back to the stand.
Think of a Brick pallet. A lot more mass of brick than an oven, and designed to be forklifted onto rough ground.
And it all gets down to the strength of the stand. The amount of legs to spread the weight out. And the cross bracing to stop the lateral movement.
Regards dave

[PizzaCharlie]

Re: Valoriani 100 Sydney Build

Thanks cobbler. I see where you're coming from.
But in terms of insulation. I read on here Time and time again you can never have enough insulation.

I guess that's why I've planned that extra layer of cement. Are the hebel bricks enough insulation? I can go 75mm.
Do I need a vermiculite in the cement slab? If I need the extra slab at all at the base.

The stand will be strong enough to hold a couple of elephants. A metal worker mate of mine is getting done for me. So I'm not worried about the strength of the stand just the proper base of the oven in terms of insulation.

If I could avoid the slab of cement I would prefer that just to make the stand light enough to move around.

[cobblerdave]

Re: Valoriani 100 Sydney Build

G'day
The concrete top on the FB stand is just to hold up the oven. It has no insulation value at all. In fact the insulation isolates the oven from the stand. If the insulation wasn't there the concrete would act as a heat sink and wick away heat from the oven making it hard to manage and keep to temp.
Yes you can use hebel as insulation. My own oven has 50 mm of hebel as hearth insulation and works well enough. Cement based produces however can be effected by high heat so I always recommend 25 mm of other insulation on top of it just in case.
Regards dave

[seamad]

Re: Valoriani 100 Sydney Build

Here is a piccy of my frame, on top of steel is hebel power panel ( not bricks ) and then the insulation layer, ceramic board, insulates very well and overall much lighter than a concrete slab or even fibre cement sheeting.

[david s]

Re: Valoriani 100 Sydney Build

Your stand looks pretty solid, but have you got some bracing underneath the Hebel panels? I ask this because I used Hebel power panel (which has 5 mm steel reinforcing cast into the middle of each panel), for my little mobile oven. The Hebel panels 75mm thick sit on a steel stand. They have cracked pretty badly and I don't believe they are particularly strong. Whether they cracked from heat (I did not use any other insulation between the Hebel and the oven floor apart from a 1" layer of 5:1 vermicrete), or travelling over rough roads and speed bumps, is anyone's guess, but when I build the next one I won't be doing it this way again.

[seamad]

Re: Valoriani 100 Sydney Build

David, I don't think the hebel would like a lot of movement ( towed behind a car type ) and with 30mm or so of vermicrete I'd reckon there would be some heat damage as well. Luckily mine is staying put, and there is extra steel underneath as well..

As far as the OP goes, I understood that his was on a metal stand with wheels to move it @, not tow it behind a car. By using a permanently flexible adhesive between the steel and hebel the hebel should be fine. The ground it sits on will have to be pretty smooth anyway as the oven alone without stand, flue/outer arch/insulation is 280kg, so trying to roll that over bumpy bits would be tricky. I'd be using hebel as its easy to use, light and it's an insulator as well. The stand design is probably a more important considertaion , there is going to be a bit of weight involved.

[PizzaCharlie]

Re: Valoriani 100 Sydney Build

It took a while but finally some movement.



This is the base stand + wheels. 140cm LxW
Strong and heavy as an elephant. Because of the very heavy weight I'm reconsidering the concrete slab.
The red paint is a primer for the rust.

Now I'm tossing up between a layer of blue board that we have under the house or the sheet of compressed concrete. And lay the hebel blocks ontop.

The concrete slab will make it too heavy.