Bricks required for a 43" oven

[Hendo]

Oven Height

I think you want to pick your oven hearth height based on the level that would be comfortable to slide pizza in and out of the oven - keep in mind that to slide it in you want the peel tilted up at an angle to allow the pizza to slip off. I think this generally gives you a lower oven than what might be comfortable to look into.

Maver,
Thanks for this practical advice - I hadn't considered the angle required for the peel, and will take this into account.

[james]

Lot's going on here.

Hendo, can you take a photo of a tapered brick? I'm having trouble getting a mental picture of how they would work. If you could stack a couple of them, and post the photo, that would help me see how this might go.

If the bricks are not right for brick oven cooking, or more expensive, I am not sure I see a strong advantage. Virtually all of the ovens built from the Pompeii plans use standard shape bricks, where the inward angle is set either with wedges or forms.

On Oven height, make sure your cooking floor is not so low that you have to stoop over to see in the oven. I think you are working inside the oven more with a pizza oven (setting and moving pizzas every few seconds) than you would in a commercial bread oven -- where you set the bread and come back in 30 minutes. That might be why the instructions you see for Breadbuilder's style oven might be lower. I like the oven floor up at about 42", or even more.

And lastly -- the views in the valleys south of Florence sure are pretty. The land in gentle, rolling and green. Between the olive tree, cypress, umbrella pine and the winter wheat -- it's even green in the middle of winter. There is something very relaxing about it.

Enjoy your project.
James

[Hendo]

Hendo, can you take a photo of a tapered brick? I'm having trouble getting a mental picture of how they would work. If you could stack a couple of them, and post the photo, that would help me see how this might go.
James

James,

See photo at http://www.consolidatedrefractories.com.au/dense.htm

This company stocks fire bricks manufactured by the same firm which sells the "kit" that Carioca has spoken about. I assume that the white ones towards the left of the photo are, or are similar to, the tapered bricks in the kit.

If so, they would require cutting accurately in half along their length to use in the dome. This would then obviate the need for wedges during construction, provided the angle of the taper was exactly that required for the diameter of oven under construction.

I will endeavour to contact the local distributor of these tapered bricks next week to confirm.

[carioca]

cut

If so, they would require cutting accurately in half along their length to use in the dome. This would then obviate the need for wedges during construction, provided the angle of the taper was exactly that required for the diameter of oven under construction.

I will endeavour to contact the local distributor of these tapered bricks next week to confirm.

Hendo, James, I've been told by the Darley people that the bricks are tapered across the WIDTH (i.e. from 75 mm down to 53 mm or whatever), so they'd have to be cut in half across the LENGTH od 230 mm to get to equal pieces with the same taper...

Cheers,

Carioca

[carioca]

the dome 'kit' is round!

Hello Hendo (I believe itwas you who wondered about the shape of the oven 'kit'?!):

straight from the horse's mouth a few minutes ago and in writing - the pizza oven 'kits' are for a round dome!

The diameters are the OUTSIDE diameters.

Their 25 mm Calsil insulation board is considered more than adequate - you'd pay double for 50 mm and gain little advantage (I'm quoting the supplyer's spokesperson, Tonia Taylor)...

Cheers,

Carioca

NB: Did you receive the forwarded BH&G article on the TUNNEL oven?

[brillwills]

Re: Bricks required for a 43" oven

hi
reading thru the articles listed for the quantity of Firebricks needed to build a dome 1meter in diameter (+-42") roughly 32 brick in the base course these would be "Snap Headers" (Full brick cut in half)

what im getting at is are the quantity's for full bricks and if so how many does it take to complete the dome , the floor would be around 60 if laid on edge and 50 laid flat ....

Im planning on building 1 in my garden (well ive already started) base being 1.8 m wide and 1.9 long to allow for front hearth , just shuttered cooking hearth ready for 150mm slab , im going to build the dome with firebrick internal skin using a sand cement lime mortar and 25mm foil backed insulation board (kingspan), I want to place a twisted chimney centrally on the dome for a feature but im unsure whether this may allow to much heat to vent too quickly ? and also if the concrete collar i would have to form for this stack to sit on would withstand the heat , I'll post some pix as i go but appreciate any feedback with your experiences in the meantime thanks paul

[Andy]

Re: Bricks required for a 43" oven

Hi Brilllwills,
I'm in the uk and just starting to build the beast. I'm not sure what you mean by a central chimney... I think you need an external chimney to make the oven work, with an internal chimney exiting from the top of the dome the bulk of the heat energy will be lost to your oven.

[brillwills]

Re: Bricks required for a 43" oven

Hi Andy
Thanks for the reply
I can only think that all will not be lost if i place a heat deflector (metal plate over the hole) to stop the heat from the hearth escaping too quickly through a centraly placed stack , could do a tradtional one but for visual effect a twisted stack would be better

any help or experience would be appreciated

cheeers paul (brillwills)

[dmun]

Re: Bricks required for a 43" oven

I want to place a twisted chimney centrally on the dome for a feature but im unsure whether this may allow to much heat to vent too quickly ? and also if the concrete collar i would have to form for this stack to sit on would withstand the heat

You MUST NOT vent the oven from the top of the dome. This has been tried repeatedly and nothing causes more heat losses except a lack of insulation. If you want a central chimney as a decorative feature, you need to have an offset flue from the entry, to the central point. Think about it: would you leave a skylight open in your house all winter? How could you ever stay warm with all the heat exiting straight up?

As to whether a dome will support a massive masonry chimney on top, I would plan on some method of supporting the chimney independent of the dome. The dome expands and contracts with the heat of firing, and has a tendency to crack even when not load bearing. I built a very large chimney on top of my oven, and built a reinforced concrete bridge over the dome to support it. That may be overkill, but I would design your exterior cover to bear the weight of the central chimney.

[dmun]

Re: Bricks required for a 43" oven

Two more things:

sand cement lime mortar

This sounds like ordinary masons mortar. It will crumble with heat if you use it to lay up your firebricks. If you want to make your own mortar, look into the fireclay/sand/portland mix recommended here.

25mm foil backed insulation board (kingspan)

Most foil backed insulations are made for domestic use, the foil is a vapor barier, and they are unsuitable for high heat uses. You want a specific insulation used for refractory purposes, or make your own from garden vermiculite and portland cement.

The reason domestic insulation doesn't work is that it contains organic binders that smoke (and stink) in high heat applications.

[dmun]

Re: Bricks required for a 43" oven

(from another thread)

thanks for the reply ,
like the look of your project using the triangle technique which should equate to an extremely strong design, Im building mine using a ply rib shutter as a former and plain old half brick laid in a lime mortar backing no internal joints or beds backed off with a 50mm Vermiculite concrete render shaped with a dolly and final face brick course topped of with a twisted stack (Decorative only) im going to rely on convection to vent the smoke out of the front opening , trying to source materials at fair prices here in the Uk is pretty difficult $3 a brick makes for a pretty hefty bill $1100 build cost ! I could buy a Neff Oven for 1/2 that

Lets see? Ply rib shutter as a former? I have no idea what that means. Maybe a sketch or a picture of what you have in mind?

Plain brick (no holes) can make an adequate dome. It's better than no oven at all.

Do i have this right? You're going to build a decorative chimney and then not use it? I'm really scratching my head over that one. Do you want all those hot exhaust gases in your face when your cooking? When you already built a chimney? It's not that hard to build a path from your entry to your central chimney, and it's going to make your oven much more usable.

Just for the record, two inches (50 mm) of vermiculite concrete is about half what you need, at a minimum. You will want four inches, or two inches of the refractory insulation blanket.

[brillwills]

Re: Bricks required for a 43" oven

The ply ribs form the template o your dome and are made to sit on a stool supported by a single post the ribs are set at 75mm centres , remove the post at the completion of your dome and you could reuse them to help out a friend when they want a pizza oven!! ? .....hey guys well all need a hand ...and dont forget were building a bit of fun not a "magnox Reactor" appreciate the feedback and will post some pix when i figure out how to ?

PS how do i win the central chimney saga

[gvzepp]

Re: Bricks required for a 43" oven

Hi All,

Just joined this forum yesterday and had to smile as already the information here has helped me track down the materials in Australia I haven't been able to do myself for my oven build.
Thanks Carioca i've spoken to Darley Refractories in Bacchus Marsh and they have some of the bits i've been chasing for quite some time now.

Regards:

Brett