newbie need advise for my oven

[gonzo420]

It's been long due.. been wanting to do this for the last 2 yrs.
Got a hold of a mishmash of fire bricks form an old factory (used for kiln) last week.

Been roaming FB site and Rado's too, but every day that I read more and more I feel like building a space shuttle.. or in other words; it's gets me more confused and the urge to be a perfectionist comes up (but on a tight budget).
But bottom line -I'm renting and wish to spend as little as possible on it, and it's gonna be a way to practice before I build one on a trailer/truck. (I wanna be able to remove it one day when moving out of current rental)

I don't know how to calculate the 68% doorway and where to position the chimney etc'.. can I get away with a rectangle shape or dome it?

I got this fire tile, tested it on my outdoor gas burner and this tile went to 170 Celsius in less than 3 min! It might be actually bad for the pizza base if it will be hotter than the rest of the oven



I wanna use this insulating brick under the floor and where ever possible, this is the light weight brick easy to cut too.


To dome or not to dome?:



rest of the photos are here:

ImageShack Album - 15 images

I was thinking of buying 2 strong metal stands to position the oven higher then shown on photos, but not sure what to use as base. (not going to slab it with concrete).

What do you guys think?

[gonzo420]

Re: newbie need advise for my oven

HAVE A LOOK AT THESE PHOTOS BEFORE!! THEY ARE THE BETTER VERSION OF THE OVEN'S DESIGN

ImageShack Album - 13 images

[tonybaker]

Re: newbie need advise for my oven

I think this has been pointed out before, anyway you say your bricks are light, maybe they are pumice mix, in which case they are a very good insulator but don't hold heat (which is what you need for pizza oven) You will need a big heat absorbing material on the floor if you use these bricks for the dome? Cut those bricks in half and make a dome, it's not hard if you do a little at a time, not much need for a support under the dome if you do it slowly. Buy a small angle grinder with diamond blade, and buy a brick bolster and heavy hammer, just do it!

[gonzo420]

Re: newbie need advise for my oven

I did an experiment with the light bricks by placing it on direct flame. They do hold heat! the side facing the flame raves up to more than a 100 degrees while the other side of the brick remains cool.
I think the name for it is Isolite but not 100% sure.
My plan is to use them as the floor (instead of a slab of concrete) and also as the outside of the dome+ rendering.
My cooking floor (the 60cm tiles) is not flat, and when I rest it on the bricks there is a gap (u can see in my other photos). Not sure how to tackle that problem rather than spending money on a ceramic blanket.

My oven is a little tricky, I want to build it in a way that it will be possible to dismantle one day when I move out of here and re-assemble it elsewhere.
Otherwise I'd go for the pompeii design and build something for a 100 years

I wonder if I could crush those lite bricks and perhaps mix it a little cast/plaster mix to make it hold and then I can apply it all over the oven. Sounds crazy? possible?

[brickie in oz]

Re: newbie need advise for my oven

I did an experiment with the light bricks by placing it on direct flame. They do hold heat! the side facing the flame raves up to more than a 100 degrees while the other side of the brick remains cool.
I think the name for it is Isolite but not 100% sure.

They are insulating bricks and not intended for the inside of an oven, they wont hold and retain heat for an oven.

A good dense oven brick gets saturated right through the brick, thats what keeps the oven cooking for days on end, yours wont do that.

(instead of a slab of concrete)

Dude, you seriously need to do some research on how to build an oven properly.

[david s]

Re: newbie need advise for my oven

Insulating firebricks are excellent for holding and retaining heat in the wares in a kiln, but because they have such low thermal mass cannot store much heat in themselves. In a WFO the interior is empty apart from air and the mass of the fuel so you need the mass in the floor and walls.

[gonzo420]

Re: newbie need advise for my oven

They are insulating bricks and not intended for the inside of an oven, they wont hold and retain heat for an oven.

Guys I'm not using the insulating bricks inside the oven!!

I want to use them as insulators of course, to cut some costs on ceramic blanket and to avoid pouring a slab of concrete (Please look at my photos http://imageshack.us/g/1/10243280/). I'll be moving to a new house next year what am I gonna do with a slab of concrete then?

My design is going to be a little different, I also wish to make the door arch semi removable so I can slide in large cooking trays for roasts.
I am not building a pompeii oven to last for the next 100 yrs! Just need something to cook the job done and be slightly easy to take apart when moving out.

[gonzo420]

Re: newbie need advise for my oven

Insulating firebricks are excellent for holding and retaining heat in the wares in a kiln

David do you reckon I can some how mesh some of these bricks up and mix it with some other ingredient to be used as insulating mortar?
It's just that I got a hold of a fair quantity of them for cheap so I better put them to use no? At least as my hearth that's for sure.

Saying that, anyone knows which place in Perth is the cheapest to buy ceramic blanket and refractory concrete?
I got quoted $65 for 16kg of RC and $110 for 3.6 meters of ceramic blanket (not sure of its thickness and or quality)

[david s]

Re: newbie need advise for my oven

Yes, you can smash them to create an insulation aggregate, but don't crush them to powder, you want the air in there. I've crushed plenty of insulating firebricks using a hammer, it's slow hard work.

[cobblerdave]

Re: newbie need advise for my oven

Gudday
Could they not be "mortared" together with pearlite and cement mix.
Regards dave

[david s]

Re: newbie need advise for my oven

Gudday
Could they not be "mortared" together with pearlite and cement mix.
Regards dave

Certainly can and this would be easier than crushing them. The question was can they be crushed to use as an aggregate and I answered accordingly.
Perlite or vermiculite makes a lightweight insulating mixture that is way easier than crushing insulating bricks. But if you have them and they're free they can be used as an aggregate. In my case I wanted a high temperature mix. Both perlite and vermiculite are only good for 1100 C, which is of course way more than you need for a WFO.

[gonzo420]

Re: newbie need advise for my oven

Yes, you can smash them to create an insulation aggregate, but don't crush them to powder

If I use the bricks halved or aggregate, should I mortar them together or can they remain loose? I will use mesh wire and little mortar on the dome part, then do the final layers of rendering.
If so, I don't need to spend $110 on ceramic blanket is it?

If the above is correct then I just need to buy refractory mortar, water resistant mortar (not sure what to get from Bunnings) and mesh wire and I'm good to go I hope

[david s]

Re: newbie need advise for my oven

I'd be breaking them into manageable pieces (around half a brick each piece) and fill between them like crazy paving, with homebrew insulation mix 5:1:1:1:1 (perlite or vermiculite,portland cement,sand, builders lime,bricklayers clay. This insulating layer should be at least 100 mm thick. (You don't say how thick your bricks are).This insulation layer does not have to be strong, the outer shell holds it all in place. It is the air that you want to trap in the insulation layer.

[gonzo420]

Re: newbie need advise for my oven

I'd be breaking them into manageable pieces (around half a brick each piece) and fill between them like crazy paving, This insulating layer should be at least 100 mm thick.

The bricks are 32x12 and 80mm thick, they are the same size as the fire bricks.
If you say 100mm thick then I shouldn't cut them and I'll use them 'as is' on top of the dome. I guess breaking them apart and do the homebrew mix will make the insulation better but wouldn't it be fine just like this?

I placed a firebrick on the stove this morning with the insulating one on top of it for more than an hour. The temp on top of the insulating brick was 30 degrees. on top of the fire brick was 160 and where the insulating brick touches the fire brick it was 77 degrees.


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[gonzo420]

Re: newbie need advise for my oven

I just saw an ad on gumtree for ceramic blankets
Price: $70 per roll 600mm wide x 25mm thick x 3600mm long
BUY 2 FOR $99
My bricks+ blanket= 110mm~ of insulation
So that should be good right?